中文摘要：

相变存储器（PCM）作为一种新型的非易失性存储器有望替代DRAM．针对PCM在视频应用中的使用，考虑到图像中亮度数据比色度数据更为重要，为了减少PCM的写操作能耗，延长写寿命，提出一种双阈值的近似写方法．首先分别为亮度数据和色度数据设置一个阈值寄存器，在对PCM进行写操作时根据不同的数据选择不同的阈值；然后将阈值和新旧数据之间的绝对差值进行比较，当绝对差值小于或等于阈值时禁止PCM的写操作，否则只对PCM有变化的数据位进行更新．实验结果表明，该方法能够以较低的硬件开销有效地减少PCM的写操作，且可以灵活地在写操作减少量和视频质量之间进行权衡．

英文摘要：

As an emerging non-volatile memory technology, phase change memory （PCM） is promising as an alternative to DRAM. For PCM used in video applications, given that luminance data are more critical than ehrominance data, this paper proposes a significance-aware dual-threshold approximate write scheme to reduce its write traffic and extend its lifetime. This scheme first designates different threshold registers and selects different thresholds for luminance data and chrominance data. Next it compares the chosen threshold with the absolute difference between new data and old data. If the absolute difference doesn＇t exceed the threshold, the write operations are disabled. Otherwise, only the updated bits are written. Experimental results show that the proposed method can effectively reduce the write operations of PCM with a low hardware overhead. In addition, it has the flexibility to make a trade-off between write traffic reduction and video quality.