no code implementations • 8 Sep 2020 • Wenning Zhang, Ryohei Hisano, Takaaki Ohnishi, Takayuki Mizuno
Block modeling is widely used in studies on complex networks.
no code implementations • 25 Feb 2020 • Takahiro Yoshida, Ryohei Hisano, Takaaki Ohnishi
Compared with latent Dirichlet allocation, Gaussian latent Dirichlet allocation is limited in the sense that it does not capture the polysemy of a word such as ``bank.''
no code implementations • 9 Nov 2018 • Ryohei Hisano, Didier Sornette, Takayuki Mizuno
Negative screening is one method to avoid interactions with inappropriate entities.
no code implementations • 22 Feb 2018 • Ryohei Hisano
Topic models are frequently used in machine learning owing to their high interpretability and modular structure.
no code implementations • 14 Oct 2016 • Ryohei Hisano
We propose a simple discrete time semi-supervised graph embedding approach to link prediction in dynamic networks.
no code implementations • 6 Apr 2015 • Ryohei Hisano
By exploiting interfirm buyer--seller network data, we show that the problem of estimating the interdependence of industries is similar to the problem of uncovering the latent block structure in network science literature.
no code implementations • 23 Oct 2012 • Ryohei Hisano, Didier Sornette, Takayuki Mizuno, Takaaki Ohnishi, Tsutomu Watanabe
We show that the whole landscape of news that affect stock price movements can be automatically summarized via simple regularized regressions between trading activity and news information pieces decomposed, with the help of simple topic modeling techniques, into their "thematic" features.