Response Time Driven Multimedia Data Objects Allocation for Browsing Documents in Distributed Environments

Distributed information processing, in many WWW applications, requires access to and the transfer and synchronization of large multimedia data objects (MDOs) across the communication network. Moreover, end users expect very fast response times and high QoS. Since the transfer of large MDOs across the communication network contributes to the response time observed by the end users, the problem of allocating these MDOs so as to minimize the response time is challenging. This problem becomes more complex in the context of hypermedia documents, in which the MDOs need to be synchronized during presentation to the end users. The basic problem of data allocation in distributed database environments is NP-complete. Therefore, there is a need to pursue and evaluate solutions based on heuristics which generate near-optimal MDO allocation. We address this problem by: (1) conceptualizing this problem by using a navigational model to represent hypermedia documents and their access behavior by end users, and by capturing the synchronization requirements on MDOs, (2) formulating the problem by developing a base case cost model for response time and generalizing it to incorporate user interaction and buffer memory constraints, (3) designing two algorithms to find near-optimal solutions for allocating MDOs of the hypermedia documents while adhering to the synchronization requirements, and (4) evaluating the trade-off between the time complexity to obtain the solution and the solution quality by comparing the solutions generated by the algorithms with the optimal solutions generated through an exhaustive search.