In the current Internet, the quality of service of audio application is not guaranteed due to variable loss and delay. Forward error correction (FEC)-based error control mechanisms which send the redundant information with the main information can be used to minimize the effects of packet loss. However, increasing the amount of redundancy may waste bandwidth and increase the end-to-end delay. The existing FEC-based error control mechanisms select the codec combination only based on the network loss rate. These mechanisms do not consider the end-to-end delay by increasing the amount of redundancy. This may result in exceeding the acceptable maximum delay. We propose a selection mechanism of the audio codec combination for error control. In simulations, we confirm that the proposed algorithm reduces the end-to-end delay and the packet loss together.

The NOD article makes a difference to VOD data in terms of media type, size, creation interval and user interactivity. Because of these intrinsic characteristics, user access patterns of the NOD article can be different from that of VOD data. In this paper, we analyze the log file of one electronic newspaper to show the short-term popularity and long-term popularity patterns. Based on these patterns, we propose LLBF (Largest Life-cycle Based Frequency) prefetching scheme that uses the two popularity patterns to cache a set of popular articles. In Simulation, we show that the proposed LLBF prefetching scheme increases hit ratio, and reduces the number of replacements more than other replacement algorithms as a small number of articles such as headline news is prefetched in main memory.