Zhijun Lei

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In order to transmit pre-encoded digital video over heterogeneous networks, it is necessary to employ transcoding techniques that convert pre-encoded video streams into streams having different bit rates and quality. The specified problem is referred to as rate shaping or rate adaptation. In this work, we propose a new rate control scheme for H.263+ based(More)
For video t ransmission over heterogeneous networks and devices, the compressed video stream has to be converted into a lower transmission bit rate or a small spatial resolution. The operation of converting a video in compressed format into another video also in compressed format is called Video Transcoding. The specific transcoding issue mentioned here is(More)
In this work, we investigate the problem of bit rate adaptation transcoding for transmitting video over burst-error wireless channels. In particular, we consider a scenario consisting of packet-based transmission with an Automatic Repeat reQuest (ARQ) error control scheme. We first analyze the buffering implications of inserting a video transcoder at the(More)
In wireless sensor networks, one of the main design challenges is to save severely constrained energy resources and obtain a long system lifetime. Low cost of sensors enables us to initially deploy a large number of sensor nodes in a very high density. Thus, a potential approach to solve a lifetime problem arises. That is to schedule sensor nodes work(More)