Akira Sasaki


Predicting Stances from Social Media Posts using Factorization Machines
Akira Sasaki | Kazuaki Hanawa | Naoaki Okazaki | Kentaro Inui
Proceedings of the 27th International Conference on Computational Linguistics

Social media provide platforms to express, discuss, and shape opinions about events and issues in the real world. An important step to analyze the discussions on social media and to assist in healthy decision-making is stance detection. This paper presents an approach to detect the stance of a user toward a topic based on their stances toward other topics and the social media posts of the user. We apply factorization machines, a widely used method in item recommendation, to model user preferences toward topics from the social media data. The experimental results demonstrate that users’ posts are useful to model topic preferences and therefore predict stances of silent users.


Other Topics You May Also Agree or Disagree: Modeling Inter-Topic Preferences using Tweets and Matrix Factorization
Akira Sasaki | Kazuaki Hanawa | Naoaki Okazaki | Kentaro Inui
Proceedings of the 55th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

We presents in this paper our approach for modeling inter-topic preferences of Twitter users: for example, “those who agree with the Trans-Pacific Partnership (TPP) also agree with free trade”. This kind of knowledge is useful not only for stance detection across multiple topics but also for various real-world applications including public opinion survey, electoral prediction, electoral campaigns, and online debates. In order to extract users’ preferences on Twitter, we design linguistic patterns in which people agree and disagree about specific topics (e.g., “A is completely wrong”). By applying these linguistic patterns to a collection of tweets, we extract statements agreeing and disagreeing with various topics. Inspired by previous work on item recommendation, we formalize the task of modeling inter-topic preferences as matrix factorization: representing users’ preference as a user-topic matrix and mapping both users and topics onto a latent feature space that abstracts the preferences. Our experimental results demonstrate both that our presented approach is useful in predicting missing preferences of users and that the latent vector representations of topics successfully encode inter-topic preferences.

A Crowdsourcing Approach for Annotating Causal Relation Instances in Wikipedia
Kazuaki Hanawa | Akira Sasaki | Naoaki Okazaki | Kentaro Inui
Proceedings of the 31st Pacific Asia Conference on Language, Information and Computation


Annotating Geographical Entities on Microblog Text
Koji Matsuda | Akira Sasaki | Naoaki Okazaki | Kentaro Inui
Proceedings of the 9th Linguistic Annotation Workshop