Study of Entity-Topic Models for OOV Proper Name Retrieval
Résumé
Retrieving Proper Names (PNs) relevant to an audio document
can improve speech recognition and content based audio-video
indexing. Latent Dirichlet Allocation (LDA) topic model has
been used to retrieve Out-Of-Vocabulary (OOV) PNs relevant to
an audio document with good recall rates. However, retrieval of
OOV PNs using LDA is affected by two issues, which we study
in this paper: (1)Word Frequency Bias (less frequent OOV PNs
are ranked lower); (2) Loss of Specificity (the reduced topic
space representation loses lexical context). Entity-Topic models
have been proposed as extensions of LDA to specifically learn
relations between words, entities (PNs) and topics. We study
OOV PN retrieval with Entity-Topic models and show that they
are also affected by word frequency bias and loss of specificity.
We evaluate our proposed methods for rare OOV PN re-ranking
and lexical context re-ranking for LDA as well as for Entity-
Topic models. The results show an improvement in both Recall
and the Mean Average Precision.