• Journal of the Optical Society of Korea
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• v.20 no.3
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• pp.335-342
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• 2016

We demonstrate an optical asynchronous transfer mode/wavelength division multiplexing (OATM/WDM) optical access network, using a router based on an optical header decoder to conduct next-generation communications. The router consists of a decoder or hardware analysis processing of the header bit and switches. The router in the OATM/WDM optical access network is a key technology by which to satisfy subscribers’ requests, including reliability, cost efficiency, high speed, large-capacity transmission, and elevated information security. In this study, we carry out experiments in which a header decoder delivers to 16 and 32 subscribers with a single wavelength in the router. These experiments confirm the decoder’s successful operation via hardware using 4 and 5 header bits. We propose that this system may significantly contribute toward the realization of an optical access network that provides high-quality service to subscribers of next-generation communications.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.131-136
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• 2005

UWB is the most spotlighted wireless technology that transmits data at very high rates using low power over a wide spectrum of frequency band. UWB technology makes it possible to transmit data at rate over 100Mbps within 10 meters. To preserve important header information, MB-OFDM UWB adopts Reed-Solomon(23,17) code. In receiver, RS decoder needs high speed and low latency using efficient hardware. In this paper, we suggest the architecture of RS decoder for MB-OFDM UWB. We adopts Modified-Euclidean algorithm for key equation solver block which is most complex in area. We suggest pipelined processing cell for this block and show the detailed architecture of syndrome, Chien search and Forney algorithm block. At last, we show the hardware implementation results of RS decoder for ASIC implementation.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.195-198
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• 2005

UWB is the most spotlighted wireless technology that transmits data at very high rates using low power over a wide spectrum of frequency band. UWB technology makes it possible to transmit data at rate over 100Mbps within 10 meters. To preserve important header information, MBOFDM UWB adopts Reed-Solomon(23,17) code. In receiver, RS decoder needs high speed and low latency using efficient hardware. In this paper, we suggest the architecture of RS decoder for MBOFDM UWB. We adopts Modified-Euclidean algorithm for key equation solver block which is most complex in area. We suggest pipelined processing cell for this block and show the detailed architecture of syndrome, Chien search and Forney algorithm block. At last, we show the hardware implementation results of RS decoder for ASIC implementation.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3668-3674
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• 2000

Recently Technology regarding VoIP (Voice over IP) is emerging over the market of the IP network. So far nothing is unfortunately there any attempt to try any research with respect to the development of the protocol stack relating to such control of gateway as MGCP, MEGACO, SIP, SDP. The reasons come from the low level of infrastructue, the shortage of the time and technology required at the moment, and so on. In this regards, this paper is focused on developing a protocol stack made with encoder/decoder, the generator of the header file etc, based on the protocol grammars of MGCP, SDP supported by IETF. For the sake of it, first develops the syntax analyzer, encoder/decoder, header file generator for encoding/decoding as applying the method of syntax-directed to each protocol grammar.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.5
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• pp.207-216
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• 2023

For decoding-compatible parallel Deflate algorithm, this study proposed a new method of the control header being made in such a way that essential information for parallel compression and decompression are stored in the Disposed Bit Area (DBA) of the non-compression block and being inserted into the compressed blocks. Through this, parallel compression and decompression are possible while maintaining perfect compatibility with the existing decoder. After applying this method, the compression time was reduced by up to 71.2% compared to the sequential processing method, and the parallel decompression time was reduced by up to 65.7%. In particular, it is well known that parallel decompression is impossible due to the structural limitations of the Deflate algorithm. However, the decoder equipped with the proposed method enables high-speed parallel decompression at the algorithm level and maintains compatibility, so that parallelly compressed data can be decoded normally by existing decoder programs.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06a
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• pp.43-46
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• 1998

MPEG-2 비디오 표준에서는 좀 더 고품위의 화질을 유지하기 위해 많은 변수들을 조절할 수 있도록 한다. MPEG-2의 header를 통해 전송되는 이러한 변수들이 MPEG 비디오 디코더에서 올바로 해석되어야 전송한 영상 신호와 동일한 신호를 수신자가 볼 수 있을 것이다. 본 논문에서는 MPEG 비디오 디코더의 정상 동작을 검사할 디코더만을 이용해 확인할 수 있도록 제작한 검사용 비트열을 소개한다. 또 공개되어 있는 검사용 비트열의 특성과 제작한 비트열의 검사방식을 software 디코더의 결과로 비교 분석한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.747-750
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• 2008

JPEG(Joint Photographic Expert Group)은 손실 압축 기법을 사용하여 데이터 양을 20:1 이상으로 현저히 줄이면서도 원 영상과 거의 유사한 영상을 복원할 수 있도록 해주기 때문에, 요즘 디지털 카메라 및 휴대폰 등 영상을 저장할 매 대부분 Exif(Exchangeable image file format)로 JPEG 압축형식을 널리 사용하고 있다. 본 논문은 JPEG 베이스라인 모드로 압축되어진 영상의 디코딩 단계에서 필요한 비계층형 헤더를 파싱하는 모듈의 기능을 소프트웨어로 모델링하고 VHDL을 이용하여 회로를 합성하고 동작을 검증하였다. 설계 결과 Xilinx xc3s1000 fg676-4 환경에서 154.488MHz의 동작속도를 나타내었고, JPEG 디코더의 고속 데이터 처리에 적응 가능하다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.3
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• pp.19-27
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• 2001

Accordingly it is very important to not only develop the stack of protocol, but also try an international standardization regarding the standard protocol of VoIP. Has compared to the advanced countries having already some success in commercialization, Korea is relatively much less involved in relation to this technology and endeavors. In this regards, this paper is focused on developing a protocol stack made with encoder/decoder, the generator or the header file, syntax analyzer etc. based on the protocol grammars of Session Description Protocol supported by IETF RFC2327. For the sake of it, first describe the SDP BNF grammar based on IETF RFC2327 Augmented BNF. And then we produce the Abstract Syntax Tree, header file generator for encoding/decoding as applying the method of syntax directed to SDP protocol grammar.

• Journal of Korea Multimedia Society
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• v.8 no.8
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• pp.1042-1050
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• 2005

This paper proposed a novel low-power video decoding scheme for mobile multimedia communication. In general, there are quite a large number of non-coded blocks in the encoded bitstream where all quantized DCT coefficients are truncated into zero. When the number of the non-coded blocks are known at the start of frame decoding, the amount of computation reduction can be precisely estimated for frame decoding. When the computation reduces, the operation speed and the corresponding supply voltage of VLSI circuits in the decoder also reduce, thus thus power consumption also reduces. In the proposed scheme, the number of the non-coded blocks is stored in the frame header of the encoded bitstream, and the decoder efficiently reduces the power consumption exploiting this information. Simulation results show that the proposed scheme reduces the power consumption to about 1/20.

• Journal of the Institute of Convergence Signal Processing
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• v.15 no.2
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• pp.30-36
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• 2014

Quality and resolution of camera in mobile device is improved significantly. In this paper, we propose block-based information hide techniques without image distortion for mobile device to solve image degradation in conventional watermarking methods. Information of image is composed with text such as camera maker, model, date, time, etc. Each text is converted to $8{\times}8$ pixel blocks and is added to the bottom of image. Generally image including block based information for image authentication are compressed using JPEG in mobile device. The vertical line value in JPEG header is modified by original size of image sensor. This technique can hide the block based authentication information using general decoder. In the experimental results, JPEG file size is slightly increased within 0.1% for the proposed block based authentication information encoding. Finally proposed methods can be adopted for various embedded systems using medical image, smart phone and DSLR camera.