Optimal online algorithms for an electronic commerce money distribution system

We consider the money distribution problem for a micro-payment scheme using a distributed server system; in particular, for an automatic charging scheme named PayPerClick that allows Internet users to view Web pages for which access charges are levied without tedious payment procedures. A major bottleneck in the scheme is the network traffic caused by the distribution of electronic money to many different servers. We propose a simple online algorithm for distributing electronic money to servers so that the network traffic is minimized. The algorithm achieves the optimal online competitive ratio. We also consider a weighted version, for which we give an asymptotically optimal online algorithm within a constant factor.