Minimum Bayes-Risk decoding with presumedword significance for speech based information retrieval

This paper addresses automatic speech recognition (ASR) oriented for speech based information retrieval (IR). Since the significance of words differs in IR, in ASR for IR, ASR performance should be evaluated based on weighted word error rate (WWER), which gives a different weight on each word recognition error from the viewpoint of IR, instead of word error rate (WER), which treats all words uniformly. In this paper, we firstly discuss an automatic estimation method of word significance (weights), and then, we perform ASR based on Minimum Bayes-Risk framework using the presumed word significance, and show that the ASR approach that minimizes WWER calculated from the presumed word weighs is effective for speech based IR.