• Journal of KIISE:Computer Systems and Theory
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• v.29 no.3
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• pp.117-124
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• 2002

This paper proposes a fault-tolerant multicasting algorithm employing the region encoding scheme in multistage interconnection networks (MIN's) containing multiple faulty switching elements. After classifying all switching elements into two subsets with equal sizes in MIN, the proposed algorithm can tolerate the faulty pattern where every fault is contained in the same subset. In order to send a multicast message to its destinations detouring faults, the proposed algorithm uses the recursive scheme that recirculates it through MIN, We prove that this algorithm can route any multicast message in only two passes through the faulty MIN.

• The KIPS Transactions:PartA
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• v.8A no.2
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• pp.99-106
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• 2001

In this paper, we study fault-tolerant multicasting in multicomputers based on multistage interconnection networks (MIN’s). In addition to one-to-one routing among processing nodes, efficient multicasting has an important effect on the performance of multicomputers. This paper presents a multicasting algorithm to tolerate faulty switching elements. The proposed algorithm uses the cube encoding scheme to represent multicast destinations in MIN, and is based on a recursive scheme in order to bypass faults. This algorithm can route any multicast message to its own destinations in only two passes through the MIN containing several faulty switching elements. Moreover, we prove the correctness of our algorithm by exploiting well-known nonblocking property of MIN.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.2C
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• pp.100-109
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• 2003

A differential index assignment scheme is proposed for the image encoding system in which a variable-length tree-structured vector quantizer is adopted. Each source vector is quantized into a terminal node of VLTSVQ and each terminal node is represented as a unique binary vector. The proposed index assignment scheme utilizes the correlation between interblocks of the image to increase the compression ratio with the image quality maintained. Simulation results show that the proposed scheme achieves a much higher compression ratio than the conventional one does and that the amount of the bit rate reduction of the proposed scheme becomes large as the correlation of the image becomes large. The proposed encoding scheme can be effectively used to encode R images whose pixel values we, in general, highly correlated with those of the neighbor pixels.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.607-610
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• 2002

Even though digital video coding techniques have been developed very rapidly, rate controlling is still an unsolved problem. This paper presents a new scene adaptive video encoding scheme for MPEG-1 and MPEG-2 video encoders. Degradation of picture quality at scene changes due to poor prediction of global complexity measure is addressed. The proposed scheme determines the picture types adaptively based on scene contents of each video frame. The effective placement of reference and inter-reference frames is studied at sudden scene changes and gradual scene changes respectively. Results show that the proposed scheme demonstrates a significant improvement in performance compared to TM5〔1〕.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1868-1871
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• 2007

This paper proposes a novel scheme to significantly reduce mode decision time by predicting optimal mode candidates. Unlike previous fast mode decision algorithms computing RDcost in a pre-defined mode order, the proposed scheme predicts optimal mode candidates and calculates their RDcosts first, increasing the possibility to satisfy early-exit conditions sooner, resulting in fast mode decision. This H.264 mode decision time reduction enables small computing power mobile devices to handle H.264 encoding effectively. Extensive simulations show that, when compared with JM10.2, AMD and LCIMS, the proposed scheme boosts H.264 encoding speed by up to 575% with a reasonable image quality degradation.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.10
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• pp.27-35
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• 1997

In this paper, we propose a new scheme for the generation of partial products for VLSI fast parallel multiplier. It adopts a new encoding method which halves the number of partial products using 2x2 submultipliers and rearrangement of primitive partial products. The true 4-input CSA can be achieved with appropriate rearrangement of primitive partial products out of 2x2 submultipliers using the newly proposed theorem on binary number system. A 16bit x 16bit multiplier has been desinged using the proposed method and simulated to prove that the method has comparable speed and area compared to booth's encoding method. Much smaller and faster multiplier could be obtained with far optimization. The proposed scheme can be easily extended to multipliers with inputs of higher resolutions.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.723-726
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• 2009

This paper describes a non-causal interpolative prediction method for B-picture encoding. Interpolative prediction uses correlations between neighboring pixels, including non-causal pixels, for high prediction performance, in contrast to the conventional prediction, using only the causal pixels. For the interpolative prediction, the optimal quantizing scheme has been investigated for preventing conding error power from expanding in the decoding process. In this paper, we extend the optimal quantization sceme to inter-frame prediction in video coding. Unlike H.264 scheme, our method uses non-causal frames adjacent to the prediction frame.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.726-742
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• 2000

A novel rte control algorithm consisting of two major components, i.e. a variable encoding frame rate method and a hybrid DCT/wavelet I-frame coding scheme, is proposed in this work for low bit rate video coding. Most existing rate control algorithms for low bit rate video focus on bit allocation at the macroblock level under a constant frame rate assumption. The proposed rate control algorithm is able to adjust the encoding frame rate at the expense of tolerable time-delay. Furthermore, an R-D optimized hybrid DCT/wavelet scheme is used for effective I-frame coding. The new rate-control algorithm attempts to achieve a good balance between spatial quality and temporal quality to enhance the overall human perceptual quality at low bit rates. It is demonstrated that the rate control algorithm achieves higher coding efficiency at low bit rates with a low additional computational cost. The variable frame rate method and hybrid I-frame coding scheme are compatible with the bi stream structure of H.263+.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.4
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• pp.463-469
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• 2016

This paper presents a compression-friendly low power test scheme in EDT environment. The proposed approach exploits scan slices reusing to reduce the switching activity during shifting for test scheme based on linear decompressor. To avoid the impact on encoding efficiency from resulting control data, a counter is utilized to generate control signals. Experimental results obtained for some larger ISCAS'89 and ITC'99 benchmark circuits illustrate that the proposed test application scheme can improve significantly the encoding efficiency of linear decompressor.

• ETRI Journal
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• v.31 no.2
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• pp.151-161
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• 2009

In this paper, we propose an adaptive multiview video coding scheme based on spatiotemporal correlation analyses using hierarchical B picture (AMVC-HBP) for the integrative encoding performances, including high compression efficiency, low complexity, fast random access, and view scalability, by integrating multiple prediction structures. We also propose an in-coding mode-switching algorithm that enables AMVC-HBP to adaptively select a better prediction structure in the encoding process without any additional complexity. Experimental results show that AMVC-HBP outperforms the previous multiview video coding scheme based on H.264/MPEG-4 AVC using the hierarchical B picture (MVC-HBP) on low complexity for 21.5%, on fast random access for about 20%, and on view scalability for 11% to 15% on average. In addition, distinct coding gain can be achieved by AMVC-HBP for dense and fast-moving sequences compared with MVC-HBP.