Rewriting logic is a unified model of concurrency, which provides a formal commo n framework of well-known models of concurrent systems. A new formal method of t he specification and execution of P systems using rewri...Rewriting logic is a unified model of concurrency, which provides a formal commo n framework of well-known models of concurrent systems. A new formal method of t he specification and execution of P systems using rewriting logic was proposed. The powerful tool Ma ude 2.0 is used to implement this specification. In order to present the general ideas in a concr ete case study, a simple and classical example from the literature is adopted to present how to formally spe cify and execute a P system.展开更多
Although the coding modes of H.264 coded video would be changed by the transcoding process of spatial resolution reduction, there exists good correlation in prediction modes and prediction directions between input and...Although the coding modes of H.264 coded video would be changed by the transcoding process of spatial resolution reduction, there exists good correlation in prediction modes and prediction directions between input and output video. In this paper, we first introduce a new spatial resolution reduction transcoding architecture of intra coded frames where the distortion can be calculated directly in compression domain. We then propose a fast mode decision algorithm in which only a small part of rate distortion optimization （RDO） calculation is needed for mode decision. For 4×4 luma block, the proposed scheme has average 21.3% computation saving, compared to the cascaded pixel-domain transcoding scheme with the fast intra mode decision algorithm proposed in JVT-G013. For 16×16 luma block, RDO calculation is completely avoided in our scheme while the scheme in JVT-G013 needs 2 RDO calculations. Experimental results show that our scheme outperforms that of JVT-G013 in terms of significantly computasavings with negligible loss of PSNR展开更多
基金National Natural Science Foundation ofChina (No. 60173033) and 973 Project( No. 2002CB312002 ) of China, andGrand Project of the Science and Tech-nology Commission of Shanghai Munici-pality ( No. 03dz15027 and No.03dz15028)
文摘Rewriting logic is a unified model of concurrency, which provides a formal commo n framework of well-known models of concurrent systems. A new formal method of t he specification and execution of P systems using rewriting logic was proposed. The powerful tool Ma ude 2.0 is used to implement this specification. In order to present the general ideas in a concr ete case study, a simple and classical example from the literature is adopted to present how to formally spe cify and execute a P system.
文摘Although the coding modes of H.264 coded video would be changed by the transcoding process of spatial resolution reduction, there exists good correlation in prediction modes and prediction directions between input and output video. In this paper, we first introduce a new spatial resolution reduction transcoding architecture of intra coded frames where the distortion can be calculated directly in compression domain. We then propose a fast mode decision algorithm in which only a small part of rate distortion optimization （RDO） calculation is needed for mode decision. For 4×4 luma block, the proposed scheme has average 21.3% computation saving, compared to the cascaded pixel-domain transcoding scheme with the fast intra mode decision algorithm proposed in JVT-G013. For 16×16 luma block, RDO calculation is completely avoided in our scheme while the scheme in JVT-G013 needs 2 RDO calculations. Experimental results show that our scheme outperforms that of JVT-G013 in terms of significantly computasavings with negligible loss of PSNR
