Model and solving methods for index data distribution on internet

The problem of optimally distributing index data objects on Internet is studied.A mathematic model was built for the problem to find a set of proxies from candidates set and to replicate objects at them.The aim is that the total access cost is minimized,subject to the constraints of the storage capacity of the proxies and the total fees charged for the proxies.This optimization problem is proved as NP-complete.Two heuristic algorithms were proposed and evaluated by simulation.The simulation results show thatthesetwo heuristics could significantly reduce the access cost.