41 citations · 44 across the 9 of their papers we have counts for
10 papers
Identifying dynamical network markers of financial market instability
Mariko I. Ito, Hiroyuki Hasada, Yudai Honma +3
Market instability has been extensively studied using mathematical approaches to characterize complex trading dynamics and detect structural change points. This study explores the…
Nondiagonal Mixture of Dirichlet Network Distributions for Analyzing a Stock Ownership Network
Wenning Zhang, Ryohei Hisano, Takaaki Ohnishi +1
Block modeling is widely used in studies on complex networks. The cornerstone model is the stochastic block model (SBM), widely used over the past decades. However, the SBM is limi…
Fractal Patterns in Spatial Distribution of Population by Age Group
Mariko I. Ito, Takaaki Ohnishi
Multifractality is one of the patterns observed in spatial distributions of populations. In this study, we performed multifractal analysis for populations by age group in the capit…
Gaussian Hierarchical Latent Dirichlet Allocation: Bringing Polysemy Back
Takahiro Yoshida, Ryohei Hisano, Takaaki Ohnishi
Topic models are widely used to discover the latent representation of a set of documents. The two canonical models are latent Dirichlet allocation, and Gaussian latent Dirichlet al…
Weighted Network Analysis of Biologically Relevant Chemical Spaces
Mariko I. Ito, Takaaki Ohnishi
In cheminformatics, network representations of the space of compounds have been suggested extensively. Among these, the threshold-network consists of nodes representing molecules.…
Novel and topical business news and their impact on stock market activities
Takayuki Mizuno, Takaaki Ohnishi, Tsutomu Watanabe
We propose an indicator to measure the degree to which a particular news article is novel, as well as an indicator to measure the degree to which a particular news item attracts at…
The gradual evolution of buyer--seller networks and their role in aggregate fluctuations
Ryohei Hisano, Tsutomu Watanabe, Takayuki Mizuno +2
Buyer--seller relationships among firms can be regarded as a longitudinal network in which the connectivity pattern evolves as each firm receives productivity shocks. Based on a da…
Structure of global buyer-supplier networks and its implications for conflict minerals regulations
Takayuki Mizuno, Takaaki Ohnishi, Tsutomu Watanabe
We investigate the structure of global inter-firm linkages using a dataset that contains information on business partners for about 400,000 firms worldwide, including all the firms…
Ecosystems perspective on financial networks: diagnostic tools
Eduardo Viegas, Misako Takayasu, Wataru Miura +4
The economical world consists of a highly interconnected and interdependent network of firms. Here we develop temporal and structural network tools to analyze the state of the econ…
High quality topic extraction from business news explains abnormal financial market volatility
Ryohei Hisano, Didier Sornette, Takayuki Mizuno +2
Understanding the mutual relationships between information flows and social activity in society today is one of the cornerstones of the social sciences. In financial economics, the…