DTW -Distance-Ordered Spoken Term Detection and STD-based Spoken Content Retrieval: Experiments at NTCIR-10 SpokenDoc-2
Tomoyosi Akiba, Tomoko Takigami, Teppei Ohno, Kenta Kase · 2013
In this paper, we report our experiments at NTCIR-10 SpokenDoc-2 task. We participated both the STD and SCR subtasks of SpokenDoc. For STD subtask, we applied novel indexing method, called metric subspace indexing, previ-ously proposed by us. One of the distinctive advantages of the method was that it could output the detection results in increasing order of distance without using any predefined threshold for the distance. In this work, we extended the al-gorithm to work with the Dynamic Time Warping (DTW) distance. We also participated in the newly introduced iSTD task by using the proposed STD method. For SCR subtask, two kinds of approaches were applied. For the lecture re-trieval task, STD-based SCR method was applied. It used STD for detecting the terms in the query from the spoken documents and their results were used to calculate the sim-ilarities between the query and documents according to the vector space model. For the passage retrieval task, we used IR models based on language modeling and focused on de-termining the optimal range of a relevant passage as the retrieval result.