Part ofAdvances in Neural Information Processing Systems 15 (NIPS 2002)
Craig Saunders, Alexei Vinokourov, John S. Shawe-taylor
In this paper we show how the generation of documents can be thought of as a k-stage Markov process, which leads to a Fisher ker(cid:173) nel from which the n-gram and string kernels can be re-constructed. The Fisher kernel view gives a more flexible insight into the string kernel and suggests how it can be parametrised in a way that re(cid:173) flects the statistics of the training corpus. Furthermore, the prob(cid:173) abilistic modelling approach suggests extending the Markov pro(cid:173) cess to consider sub-sequences of varying length, rather than the standard fixed-length approach used in the string kernel. We give a procedure for determining which sub-sequences are informative features and hence generate a Finite State Machine model, which can again be used to obtain a Fisher kernel. By adjusting the parametrisation we can also influence the weighting received by the features . In this way we are able to obtain a logarithmic weighting in a Fisher kernel. Finally, experiments are reported comparing the different kernels using the standard Bag of Words kernel as a baseline.
Requests for name changes in the electronic proceedings will be accepted with no questions asked. However name changes may cause bibliographic tracking issues. Authors are asked to consider this carefully and discuss it with their co-authors prior to requesting a name change in the electronic proceedings.
Use the "Report an Issue" link to request a name change.