QoS-oriented content delivery in e-learning systems

QoS-oriented content delivery is an important component in e-learning systems. In this paper, we study the object placement problem in the parallel-access context for QoS-oriented content delivery. The problem is formulated in terms of bandwidth maximization and further proved to be equivalent to the fault tolerant facility location problem (FTFL). In this problem the bandwidth that violates the triangle inequality is measured by a cost function which forms a metric when the shortest-path routing is deployed. Though there have been efficient UFL algorithms with good performance guarantees, the challenge of the FTFL Problem arises due to the conflict of its connectivity requirement (multiple distinct connections) and cost minimization (which leads to identical connections with the minimum cost). We investigate possible solutions for addressing this conflict after giving an overview of the existing techniques. Extension of the problem to the context of QoE-aware multimedia delivery which has important applications in e-learning systems is also discussed.