Dynamic scheduling of decoding processes for directory assistance

This paper deals with the difficult task of recognition of a large vocabulary of proper names in a directory assistance application. Research on the European project SMADA has shown that there is a need of an elaborate and effective decision strategy that limits the risk of false automation. This paper proposes a new strategy which integrates, as well as a general decoder, a set of decoders specialized in some specific situations. Specialized recognition processes do not need to be applicable for every input, but they have to be scheduled and performed only under certain conditions. A first implementation of such a model is proposed here, through a rejection strategy of the hypotheses output by a general decoder. This strategy leads to a very significant improvement over the results obtained by a standard rejection method based on acoustic confidence scores only.