1. GTTS System for the
Spoken Web Search Task
at MediaEval 2012
Amparo Varona, Mikel Penagarikano, Luis Javier Rodríguez Fuentes,
Germán Bordel, Mireia Diez
University of the Basque Country UPV/EHU
luisjavier.rodriguez@ehu.es
http://gtts.ehu.es
MediaEval 2012 - SWS Task - GTTS System - Pisa, October 4, 2012

2. HEARCH: Search on Broadcast News
(ASR + Lemmatization + Index)
MediaEval 2012 - SWS Task - GTTS System - Pisa, October 4, 2012

3. HEARCH-P: Search on Parliamentary Sessions
(Audio-Text Alignment + Index)
MediaEval 2012 - SWS Task - GTTS System - Pisa, October 4, 2012

4. Search on spoken resources
in the Internet
• Searching for text queries (computer)
• Searching for spoken queries (mobile)
• Need for a common representation:
• Acoustic (DTW-like approaches)
• Phonetic (Search on Phone-Lattices)
• Word-level (ASR-based approaches)
MediaEval 2012 - SWS Task - GTTS System - Pisa, October 4, 2012

5. SWS at MediaEval 2012
(for GTTS)
• Opportunity search onthe field resources
unrestricted
to enter
spoken
of
• Opportunity to access development and
evaluation data
• Opportunity tofield state-of-the-art from
experts in the
learn
• Our approach: search of the queries
phonetic representations
of n-best
on phone lattices of spoken resources
MediaEval 2012 - SWS Task - GTTS System - Pisa, October 4, 2012

6. GTTS System: how it works
• BUT decoders for Czech, Hungarian and Russian
• Reduced sets of phonetic classes (IPA clusters)
• Approximate string matching (n editions allowed):
Dong Wang’s Lattice2Multigram tool
• Scores: length-normalized + kind of log-likelihood ratio
with regard to all the detections in the same audio file
• Overlapped detections: only the most likely retained
• For each query: K most likely detections, z-normalization
and threshold applied
MediaEval 2012 - SWS Task - GTTS System - Pisa, October 4, 2012

7. GTTS System: how it performs
• Best configurations determined in preliminary experiments
on the development dataset
• Primary: 3-best query phone decodings, 2 editions allowed
in matchings
• Contrastive: 1-best query phone decoding, 2 editions
allowed in matchings
• Poor performance !!!
• Change in the approach: searching for the best detection of
each query in each audio document
MediaEval 2012 - SWS Task - GTTS System - Pisa, October 4, 2012

8. THANKS !!!
MediaEval 2012 - SWS Task - GTTS System - Pisa, October 4, 2012