Comparison of Retrieval Approaches and Blind Relevance Feedback Methods Within the Czech Speech Information Retrieval

This article has several objectives. First, it is to compare the most used information retrieval methods on a single speech retrieval collection. The collection, used in the CLEF 2007 Czech task, contains automatically transcribed spontaneous interviews of holocaust survivors and is to our knowledge the only Czech collection of spontaneous speech intended for speech information retrieval. Apart from the first experiments presented in the CLEF competition, no comprehensive experiments have been published on this collection to compare the different information retrieval methods. The second objective of this paper is to compare the results of using the blind relevance feedback methods with the individual retrieval methods and introduce the possibility of using the score normalization methods for the selection of documents for the blind relevance feedback. The third objective of this article is to compare different normalization methods among themselves. Exhaustive experiments were performed for each method and its settings. For all information retrieval methods used, the experiments results showed that the use of score normalization methods significantly improves the achieved retrieval score.