no code implementations • 3 Aug 2023 • Keidai Arai, Koki Yamada, Kohei Yatabe
Sparse time-frequency (T-F) representations have been an important research topic for more than several decades.
no code implementations • 11 May 2023 • Katsuki Fukumoto, Koki Yamada, Yuichi Tanaka, Hoi-To Wai
In this paper, we formulate a node clustering of time-varying graphs as an optimization problem based on spectral clustering, with a smoothness constraint of the node labels.
no code implementations • 26 Oct 2022 • Koki Yamada
A representative approach to this problem is the graph Wiener filter, which utilizes the statistical information of the target signal computed from historical data to construct an effective estimator.
no code implementations • 30 Jun 2021 • Masatoshi Nagahama, Koki Yamada, Yuichi Tanaka, Stanley H. Chan, Yonina C. Eldar
We overcome two main challenges in existing graph signal restoration methods: 1) limited performance of convex optimization algorithms due to fixed parameters which are often determined manually.
no code implementations • 27 Oct 2020 • Kazuma Iwata, Koki Yamada, Yuichi Tanaka
We propose a blind deconvolution method for signals on graphs, with the exact sparseness constraint for the original signal.
no code implementations • 10 Jan 2020 • Koki Yamada, Yuichi Tanaka, Antonio Ortega
We propose a novel framework for learning time-varying graphs from spatiotemporal measurements.