On periodic resource scheduling for continuous media databases

The Enhanced Pay-Per-View (EPPV) service model provides an effective way of delivering continuous media (CM) data clips to a large number of different clients. The aim is to share CM streams among various clients, thereby increasing the level of concurrency beyond the capacity limitations of available resources, while guaranteeing an upper bound on the clients' waiting time. In the EPPV service model, waiting time guarantees are provided by means of a regular playback schedule, where each continuous media clip is displayed periodically with a frequency that depends on factors such as the clip's popularity. Efficiency is achieved by sharing these periodic CM streams among multiple clients. The EPPV model offers a number of advantages over other schemes, which makes it more attractive to large-scale service providers. This paper provides an overview of our recent results on the resource scheduling problems associated with supporting EPPV for continuous media clips with (possibly) different display rates, frequencies, and lengths; and outlines a number of open research problems related to the EPPV service model. 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.