Static index pruning for information retrieval systems
David Carmel, Doron Cohen, et al.
SIGIR Forum (ACM Special Interest Group on Information Retrieval)
We introduce backoff processes, an idealized stochastic model of browsing on the World Wide Web, which incorporates both hyperlink traversals and use of the "back button." With some probability the next state is generated by a distribution over out-edges from the current state, as in a traditional Markov chain. With the remaining probability, however, the next state is generated by clicking on the back button and returning to the state from which the current state was entered by a "forward step." Repeated clicks on the back button require access to increasingly distant history. We show that this process has fascinating similarities to and differences from Markov chains. In particular, we prove that, like Markov chains, back-off processes always have a limit distribution, and we give algorithms to compute this distribution. Unlike Markov chains, the limit distribution may depend on the start state.
David Carmel, Doron Cohen, et al.
SIGIR Forum (ACM Special Interest Group on Information Retrieval)
Ronald Fagin, Phokion G. Kolaitis
SIGMOD/PODS 2012
Yoshito Hanatani, Ronald Fagin
Information Processing Letters
Ronald Fagin, Joseph Y. Halpern, et al.
Distributed Computing