ARMA Brain Clustering Grassmannian Kernel Networks
•Proposed framework can tackle all possible clustering tasks in dynamic (brain) networks.•Latent non-linear and causal dependencies are captured by kernel (vector-valued) autoregressive-moving-average model.•Clustering algorithm exploit the underlying Riemannian geometry without the need to know the number of clusters a-priori.•Tests on synthetic and real data show favorable performance of the proposed scheme over state-of-the-art methods.
This paper demonstrates that all clustering tasks in a dynamic (brain) network, i.e., state clustering, community detection, and subnetwork state-sequence clustering, can be addressed by a novel unifying network-clustering framework. The connecting threads of the components of the proposed framework are: a novel kernel-based autoregressive-moving-average (ARMA) model which propels feature extraction from the network time-series, and the Riemannian geometry of the Grassmann manifold (Grassmannian) into which the extracted features are mapped. Clustering of the Grassmannian features is performed via the novel extension of a recently introduced algorithm which capitalizes on the Grassmannian distances and angular information of the point-cloud of features. Numerical tests on synthetic and real functional-magnetic-resonance-imaging (fMRI) data showcase the favorable performance of the proposed scheme against state-of-the-art network-clustering and manifold-learning methods, and corroborate the claim of this paper that the proposed framework can serve as a useful data-analytic toolbox for network(-neuroscience) research.