"On periodic resource scheduling for continuous-media databases"
by Minos N. Garofalakis, Banu Özden, and
The VLDB Journal,
Vol. 7, No. 4, December 1998 (Special Issue on Multimedia Databases),
The Enhanced Pay-Per-View (EPPV) model for providing
continuous media services associates with each continuous
media clip a display frequency that depends on the clip's
The aim is to increase the number of clients that can be
serviced concurrently beyond the capacity limitations of
available resources, while guaranteeing a constraint on
the response time.
This is achieved by sharing periodic continuous media
streams among multiple clients.
The EPPV model offers a number of advantages over other data
sharing schemes (e.g., batching), which make it more attractive
to large-scale service providers.
In this paper, we provide a comprehensive study of the resource
scheduling problems associated with supporting EPPV for continuous
media clips with (possibly) different display rates, frequencies,
Our main objective is to maximize the amount of disk bandwidth that
is effectively scheduled under the given data layout and storage
Our formulation gives rise to NP-hard combinatorial optimization
problems that fall within the realm of hard real-time scheduling
Given the intractability of the problems, we propose novel heuristic
solutions with polynomial-time complexity.
We also present preliminary experimental results for the average case behavior
of the proposed scheduling schemes and examine how they compare to each other
under different workloads.
A major contribution of our work is the introduction of a robust scheduling
framework that, we believe, can provide solutions for a variety of realistic
EPPV resource scheduling scenarios, as well as any scheduling problem involving
regular, periodic use of a shared resource.
Based on this framework, we propose various interesting research directions
for extending the results presented in this paper.
Copyright © 1998, Springer-Verlag.
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