The 1997 Bbn Byblos System Applied to Broadcast News Transcription

In this paper, we describe the BBN Byblos system used for the 1997 DARPA Hub-4 Broadcast News evaluation and discuss numerous improvements made to the system in 1997. We focused our e ort entirely upon the two conditions containing studio-quality uncorrupted speech from native speakers, the so-called F0 (prepared speech) and F1 (spontaneous speech) conditions. In particular, we did not bother to create a separate acoustic model for narrow-band telephone speech. Our overall 1997 Hub-4 evaluation result was 20.4% WER, but our error rate on the F0/F1 conditions was only 14%. We ran regression tests on development test data that show we reduced word error rate by 22-30% on the F0/F1 conditions compared to our 1996 system. Sizable gains were achieved on all the other conditions as well, even though no extra e ort was spent toward improving them. Brief summaries of three related e orts are also given covering the use of Byblos for Spanish news transcription, near real-time transcription, and automatic extraction of named entities from broadcast news.