Abstract

This work further develops and analyses the large vocabulary continuous speech recognition (LVCSR) search strategy reported at ICASSP-95 [1]. In particular, the posteriorbased phone deactivation pruning approach has been extended to include phone-dependent thresholds and an improved estimate of the least upper bound on the utterance log-probability has been developed. Analysis of the pruning procedures and of the search's interaction with the language model has also been performed. Experiments were carried out using the ARPA North American Business News task with a 20,000 word vocabulary and a trigram language model. As a result of these improvements and analyses, the computational cost of the recognition process performed by the noway decoder has been substantially reduced. 1. INTRODUCTION At ICASSP-95, we introduced an efficient search procedure [1] that was implemented as a software decoder known as noway and used in the Abbot hybrid connectionist/ HMM LVCSR system [2, 3]. Key fea...

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