• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1295-1305
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• 1999

In this paper, we present the implementation and performance analysis of H.324M mobile multimedia terminal which s under standardization. The H.324M is the mobile extension of H.324 which is the standard for low bit rate multimedia terminals operating over GSTN. For H.324M, the multiplexing protocol (H.223) of H.324 is enhanced to protect data from the transmission errors over mobile channels. The multiplexing protocol of H.324M is classified into Levels 0, 1, 2, and 3 depending on the level of error protection. Each Level is analyzed according to different types of the data loss elements. Simulation results show that the loss caused by the corrupted flag and header produces the most serious performance degradation. Levels 1 and 2 which protect the header and flag are effective in reducing the total loss. Furthermore, the optimal flag length and threshold value for Levels 1 and 2 are determined.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.203-216
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• 2004

Recent advances in video coding technology have resulted in rapid growth of application in mobile communication, With this explosive growth reliable transmission and error resilient technique become increasingly necessary to offer high quality multimedia service. In this paper, we present the result of our investigation on the error resilient performance evaluation of the MPEG-4 simple profile under the H.324/M and the H.264/AVC baseline under the IP packet networks. Especially, we have tested error resilient tools of MPEG-4 simple profile such as resynchronization marker insertion, data partitioning, and of H.264/AVC baseline such as the flexible macroblock ordering (FMO) scheme. The objective quality of decoded video is measured in terms of rate and PSNR under various random bit and burst error conditions.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.5
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• pp.477-485
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• 2002

In this paper, we present an efficient hardware architecture for the H.263 video codec and its VLSI implementation. This architecture is based on the unified interface by which internal hardware engines and an internal RISC processor are connected one another. The unified interface enables the modular design of internal blocks, efficient hardware/software partitioning, and pipelined paralled operations. The developed VLSI supports the H.263 version 2 profile 3 @ level 10, and moreover, both the control protocol H.245 and the multiplexing protocol H.223. Therefore, it can be used for the complete ITU-T H.324 or 3GPP 3G 324M multimedia processor with the help of an external audio codec. Simultaneous encoding and decoding of QCIF format images at a rate greater than 15 frames per second is achieved at 40 MHz clock frequency.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06b
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• pp.344-349
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• 2007

무선 통신 환경에서 실시간 화상 통신을 위해 제안된 3G-324M 프로토콜은 회선 교환 통신을 사용함으로 인해 제한된 대역폭을 이용해야만 하므로 전송 시 여러 가지 제약이 발생하게 된다. 특히 송수신의 스케줄링을 효율적으로 하지 못할 경우 H.223 프로토콜에서 매 타임 슬롯마다 전송 가능한 최대 크기의 데이터를 전송 버퍼에 채워주지 못해 전송 지연 시간이 발생하게 된다. 본 논문에서는 이러한 문제들을 해결하기 위한 통신 스케줄링 기법을 제시한다. 이 통신 스케줄링 기법은 화상 프레임의 종류에 따라 크기가 크게 변한다는 사실에 기초해 H.223 프로토콜의 실행 비율을 임시적으로 증가시켜 지연시간이 늘어나는 것을 최소화하고 이로 인해 내부 버퍼 사용량을 줄일 수 있도록 한다. 또 수신 버퍼에 처리해야 할 데이터가 많은 경우, 임시로 H.223 프로토콜의 실행 비율을 증가시켜 불필요한 수신 지연 시간이 발생하지 않도록 한다. 실험은 내부 버퍼의 사용량은 제안한 통신 스케줄링 기법이 다른 통신 스케줄링 기법들에 비해 효율적으로 관리 되며 패킷의 손실률, 수신 단말기에서의 지연이 줄어드는 것을 보여준다.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.324.2-324
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• 2001

• Bulletin of the Korean Chemical Society
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• v.22 no.3
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• pp.321-324
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• 2001

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.323-324
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• 2010

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1998.10a
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• pp.495-498
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• 1998

• Bulletin of the Korean Chemical Society
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• v.18 no.3
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• pp.324-327
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• 1997

Water soluble iridium complex, IrCl(CO)(TPPTS)2·χH2O (1) (TPPTS=m-trisulfonated triphenylphosphine) has been prepared from the reaction of a water soluble complex, IrCl(COD)(TPPTS)2·6H2O (COD=l,5-cyclooctadiene) with CO and unambiguously characterized by electronic absorption, 31P NMR, 13C NMR and IR spectral data. Complex 1 catalyzes the hydration of terminal alkynes to give ketones in aqueous solutions at room temperature. The rate of PhC≡CH hydration dramatically increases with addition of MeOH to the reaction mixture in H2O, which is understood in terms of i) the excellent miscibility between H2O and MeOH and ii) the assumed catalytic hydration pathway involving the initial formation of (alkyne)IrCl(CO)(TPPTS)2.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.323-324
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• 2012