Spoken Document Retrieval for Oral Presentations Integrating Global Document Similarities into Local Document Similarities

A spoken document retrieval (SDR) method for oral presentations is addressed. We propose an integration method of global information and local information based on a topic hierarchy of presentations. Specifically, for detecting a part of an oral presentation about one to two minutes (local document), we integrate similarities between a given query and longer units (global documents), for example a whole presentation, into a similarity between the given query and a local document contained in the global documents. For a short speech segment retrieval task from 604-hours presentation speech, we confirmed a statistical improvement of information retrieval performance.