• Journal of Broadcast Engineering
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• v.2 no.1
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• pp.45-55
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• 1997

In this paper, we propose a fast algorithm with adaptive thresholding for the wavelet transform (WT) based blocking artifact reduction. In the fast algorithm, all processings that are equivalent to the processing in WT domain of the first and second scale are performed in spatial domain. In the adaptive thresholding, the threshold values used to classify the block boundary are selected adaptively according to each input image by using the statistical properties of the WT of the coded signal at block boundary and at block center, which can be obtained in spatial domain. Experimental results showed that the proposed fast algorithm is about 10 times faster than the WT-based algorithm. It also was found that the postprocessing with proposed adaptive thresholding yields some PSNR improvement and better subjective quality over that with nonadaptive thresholding which has best performance at high compression ratios of a certain .image, even at low compression ratios.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.5
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• pp.25-32
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• 2007

This paper proposes a distributed space-frequency block code (SFBC) for relay-assisted single carrier frequency-domain equalization (SC-FDE). The proposed technique achieves spatial diversity gain over fast fading channels without the complexity of multiple antennas. The mobile equipment of the proposed system has a very simple transmitter structure with constant amplitude transmit sequences, which is desirable especially for uplink communications. In order to obtain spatial diversity, the transmit sequence of relay is efficiently generated in the time domain, which is equivalent to the SFBC. Further, efficient implementation of relay and destination structures is also presented. Extensive simulation results show that the proposed system significantly outperforms the distributed space-time block code (D-STBC) SC-FDE over fast fading channels.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.669-680
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• 2005

It is very difficult to determine the failure block scale in great rock slopes. Especially, postulating entire slope domain as a failure block without attention to discontinuity trace lenth makes very confuse and difficult to design rock slopes. In this paper, we estimate realistic failure block scale using joint system simulation method and introduce the application procedures on rock slope analysis. Besides, presenting how joint characteristics measurement and statistical analysis results are applicated to slope stability analysis design flow.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.329-330
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• 2006

This paper presents a recovery technique for images with block-based corruption by transmission losses. Conventional methods that do not consider edge directions can cause blocked blurring artifacts. In this paper, we present a block recovery scheme using Haar wavelet features. The adaptive selection of neighboring blocks is performed based on the energy ratio f wavelet subbands. The lost blocks are recovered by linear interpolation in the spatial domain using selected block pairs. The proposed directional recovery method is effective for the strong edge because it exploits the varying neighboring blocks adaptively according to the edges and the directional information in the image. The proposed method outperforms the previous methods that used only a predefined set of neighboring blocks.

• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.71-75
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• 1998

Segmented block copolymer인 polyurethane은 열역학적으로 불친화성을 갖는 두 segment unit (Hard segment unit과 Soft segment unit)에 의해 미세 상분리 현상이 나타나며 그 결과 hard-segment-rich hard domain과 soft-segment-rich soft matrix 구조를 갖는다. 상온보다 높은 유리전이온도를 갖는 hard segment와 낮은 유리전이온도를 갖는 soft segment의 특성으로 인해 polyurethane은 열가소성 탄성체의 성질을 갖으며 두 성분의 조성비에 따라 넓은 범위의 역학적인 성질을 나타낸다.(중략)

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.133-136
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• 2003

In this paper, we propose a low bit-rate embedded video coding scheme with 3-D block partition in the wavelet domain. The proposed video coding scheme includes multi-level three dimensional dyadic wavelet decomposition, raster scanning within each subband, partitioning of blocks, and adaptive arithmetic entropy coding. Although the proposed video coding scheme is quite simple, it produces bit-streams with good features, including SNR scalability from the embedded nature. Experimental results demonstrate that the proposed video coding scheme is quite competitive to other good wavelet-based video coders in the literature.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.6
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• pp.1005-1012
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• 1987

An adaptive scalar DCT-Wiener filtering method that can be applied to the problem of restoring an image degraded by white Gaussian noise is presented. In this method, the power spectrum needed to Winer filering is adaptively estimated in block-wise according to the lical properties in transform domain. In addition, overlapping method for reducing the block artifact is considered. Experimental results show that the adaptive Wiener filter by the proposed method yields performance improvement and better image quality over the nonadaptive one and the spatial Lee filter.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.454-462
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• 1997

Thermotropic block copolyester(TLCP-b-PBN) based on poly(tetramethylene 2,6-(naphthaloyldioxy)dibenzoates)(TLCP) and poly(butylene 2,6-naphthalate)(PBN) was synthesized by solution polycondensation and melt-blended with poly(ethylene 2,6-naphthalate)(PEN) for in-situ composites. The TLCP domains showed nematic behavior in melt. The composition of block copolymer was determined from $^1H-NMR$ spectroscopy. The DSC thermogram of block copolymer revealed the presence of two major melting transitions, corresponding to the separete melting of PBN and TLCP domains. The glass transition temperature(Tg) of the PEN in the blends decreased with increasing the content of TLCP-b-PBN and the TLCP-b-PBN acted as a nucleating agent for the matrix polymers. In the 20% TLCP-b-PBN blend, well oriented TLCP fibriles were observed at temperature above the melting point of the PEN by optical microscopy. By scanning electron micrographs of cryogenically fractured surfaces of extruded blends, the TLCp domains were found to be finely and uniformely dispersed in 0.15 to $0.2{\mu}m$ size. Interfacial adhesion between the TLCP and matrix polymer was seemed to be good. Under certain condition TLCP formed a fiver structure in the PEN matrix, with thin oriented TLCP fibril in the skin region and spherical TLCP domains in the core.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.213-216
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• 2003

In this paper, we propose a digital watermarking method using the spread spectrum techniques in DCT domain. Watermark is embedded in the middle band frequencies of 8$\times$8 DCT block. Therefore, we improve image quality and robustness. Experiment results show that the proposed watermark is robust against various attack.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.101-102
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• 2006

Similar to Orthogonal Frequency Division Multiplexing (OFDM), a Single Carrier with Frequency Domain Equalization (SC-FDE) system is computationally efficient since equalization is performed on a block of data in the frequency domain. In coherent QAM schemes, the mean phase rotation error caused by the residual carrier frequency offset may lead to serious degradation. When the frequency equalizer is combined with the mean phase error tracking algorithm, its performance can be enhanced noticeably.