7th International Conference on Spoken Language Processing
September 16-20, 2002
We present an algorithm for hierarchical grammar optimization achieving time and space efficiency in Automatic Speech Recognition (ASR). The algorithm includes two parts: a selective grammar expansion algorithm and a graph reduction algorithm. The latter algorithm includes a node-merging procedure and an arc-sharing procedure. The algorithm is general so as to handle all types of grammar used in ASR; it is efficient so as to process dynamically generated grammars online; it is flexible and accepts several parameters controlling tradeoff between time and space complexity in favor of various different application requirements. We used this algorithm to optimize a grammar representing a class-based trigram language model, and obtained significant grammar size reduction and a 140% recognition speedup.
Bibliographic reference. Zheng, Jing / Franco, Horacio (2002): "Fast hierarchical grammar optimization algorithm toward time and space efficiency", In ICSLP-2002, 393-396.