Shuji Tasaka

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The dynamic behavior of the R-ALOHA packet broadcast system with multipacket messages is analyzed in this paper. It is assumed that each user handles one message at a time and the number of packets in a message is geometrically distributed. A Markovian model of the system is first formulated which explicitly contains the influence of the propagation delay(More)
This paper proposes a transport–layer error recovery scheme using retransmission for live audio–video streams transferred over QoS non-guaranteed networks. The scheme employs an enhanced version of the virtual–time rendering (VTR) media synchronization algorithm, which adjusts media rendering–time according to the network condition, and is referred to as(More)
— This paper investigates the effect of the mean and jitter of end–to–end delay on user–level QoS of live audio-video transmission. The temporal structure of continuous media can be disturbed by delay jitter of packets. The temporal disturbance causes subjective degradation of the media. On the other hand, long end–to–end delay also degrades quality of live(More)
This paper quantitatively evaluates the mutually compensatory property in audio–video transmission over the Internet by the psychometric method. In our previous study, we used MOS (Mean Opinion Score) as the user–level QoS parameter; however, MOS is an ordinal scale, and therefore, its value does not necessarily represent exact difference between the(More)