Term rewriting and beyond — theorem proving in Isabelle

The subject of this paper is theorem proving based on rewriting and induction. Both principles are implemented as tactics within the generic theorem prover Isabelle. Isabelle's higher-order features enable us to go beyond first-order rewriting and express rewriting with conditionals, induction schemata, higher-order functions and program transformers. Applications include the verification and transformation of functional versions of insertion sort and quicksort.     

Counterexamples in infinitary rewriting with non-fully-extended rules

We show counterexamples exist to confluence modulo hypercollapsing subterms, fair normalisation, and the normal form property in orthogonal infinitary higher-order rewriting with non-fully-extended rules. This sets these systems apart from both fully-extended and finite systems, where no such counterexamples are possible.     

电子技术的进步与电网监控的发展

以电子元器件和计算机硬、软件技术的进步为背景,介绍了湖南、广东电网监控系统发展的过程;重点阐述了当前运行的EMS,特别是集ASC,AGC和AVC于一体的EMS的特点;展望了新一代EMS的发展方向。     

Simulation of the oregonator model by using deterministic ARMS

We propose a deterministic method for simulating chemical reactions, deterministic abstract rewriting system on multisets (DARMS), which is based on the concept of mass action low. The feasibility and utility of DARMS are demonstrated by applying it to the oregonator, which is a well-known model of the Belousov-Zhabotinskii (BZ) reaction. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Hard combinators

Hard Interaction systems can be presented as graph relabeling with a handshake mechanism that provide local synchronization. We present a particular one with only four symbols and seven rules that can be used to simulate all the other hard interaction systems.     

一种新的H.264/AVC帧内编码快速算法

针对H.264/AVC帧内编码算法采用率失真优化(RDO)算法提升编码性能导致运算复杂度增加这一问题,提出了一种新的帧内编码快速算法。该算法采用待预测块的纹理方向误差值判断待编码块的纹理特征,结合相邻块的预测模式相关性减少须遍历预测模式的数量,并结合全零块检测的提前终止判定准则加快编码速度。实验结果表明,与标准算法相比,该算法在保证输出码率和图像质量基本不变的情况下能够将帧内编码时间减少约67.2%,显著提高了H.264的帧内编码效率。     

基于兰氏距离的H.264/AVC帧内快速算法

提出了一种帧内模式快速选择算法。利用宏块内部相邻像素值的差异判定宏块的类型,再进行Intra_4×4和Intra_16×16两种模式的快速选择。对于Intra_4×4模式,利用兰氏距离提取4×4块的纹理方向,根据纹理方向进行Intra_4×4模式的快速选择。实验结果表明,所提算法在峰值信噪比(PSNR)和码率变化不大的情况下,显著地提高了编码速度。