| dc.description.abstract | One way to broadcast a popular video is to use a number of dedicated channels,each responsible for broadcasting a portion of the video periodically in a pre-defined way.Thus the stress on channels can be alleviated, and new viewers need not have to wait long to start their playback. Many approaches falling in this category have been proposed.Two representative approaches are the Fast Broadcasting scheme and the PAGODA scheme, which can broadcast a video using k channels and have new-coming viewers wait no longer than D/2^k and D/5^k/2 time,respectively,
where D is the length of the video.
This thesis consists of three parts.In the first part of the dissertation, we focus on broadcasting schemes that partition the video into a number of fixe and schemes that are scheduled to broadcast on one of the channels periodically(such as FB and PAGODA). We propose two new schemes, called Recursive Frequency-Splitting (RFS) and m-RFS.RFS tries to arrange one segment in each iteration,and m-RFS tries to arrange $m$ segments in each iteration. These two schemes significantly improve over existing schemes in terms of viewe waiting time. Some lower bounds on the waiting time are also developed.
In the second part of the dissertation, we consider a set of videos.We focuses on several representative schemes
(such as FB, PAGODA, and RFS), which all share a FSFC property by repeatedly broadcasting first segment of the video on the first channel. Here, we propose a general Borrow-and-Return model, which can be immediately applied to any scheme owning
the FSFC property, to reduce the viewers’’ waiting time without
increasing the number of channels required. Intuitively, considering a group of videos, we lend the free time slots of videos without viewers to those videos with viewers to speedup the latter’’s transmission. Later on, some bandwidth may be vacated by the latter videos to benefit others’’ transmission. Effectiveness of this model is analyzed by applying it to the FB scheme.
In the third part of the dissertation, we propose a novel seamless channel transition enhancement on top of the FB scheme to dynamically change the number of channels assigned to a video
on-the-fly. Clients currently viewing this video will not experience any disruption because of the transition. A channel allocation scheme is also proposed based on the arrival rates of videos to minimize the average waiting experienced by all viewers. From the system manager’’s point of view, the enhancement will make the FB scheme more attractive. | en_US |