Koichi Hori


2018

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Dynamic and Static Topic Model for Analyzing Time-Series Document Collections
Rem Hida | Naoya Takeishi | Takehisa Yairi | Koichi Hori
Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)

For extracting meaningful topics from texts, their structures should be considered properly. In this paper, we aim to analyze structured time-series documents such as a collection of news articles and a series of scientific papers, wherein topics evolve along time depending on multiple topics in the past and are also related to each other at each time. To this end, we propose a dynamic and static topic model, which simultaneously considers the dynamic structures of the temporal topic evolution and the static structures of the topic hierarchy at each time. We show the results of experiments on collections of scientific papers, in which the proposed method outperformed conventional models. Moreover, we show an example of extracted topic structures, which we found helpful for analyzing research activities.

1986

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Learning the Space of Word Meanings for Information Retrieval Systems
Koichi Hori | Seinosuke Toda | Hisashi Yasunaga
Coling 1986 Volume 1: The 11th International Conference on Computational Linguistics