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IPS273 Tomoki Tokuda et al.


                                  Multiple co-clustering with heterogenous
                                  marginal distributions and its application
                                 to identify subtypes of depressive disorder
                                                                          1
                                                              2
                        Tomoki Tokuda , Junichiro Yoshimoto , Yu Shimizu , Kenji Doya 1
                                       1,2
                          1 Okinawa Institute of Science and Technology Graduate University, JAPAN
                                   2  Nara Institute of Science and Technology, JAPAN
                  Abstract
                  With the advent of sophisticated data acquisition methods, huge amounts of
                  data have become available. Cluster analysis is a powerful data mining tool to
                  reveal the underlying heterogeneous structure of objects in data. Recently, co-
                  clustering method gains much attention for its attempt to reveal relationships
                  between  object  and feature,  hence capturing  a  possible  interplay  between
                  them. However, in a big dataset, multiple cluster structures may exist, where
                  cluster  solutions  differ  depending  on  the  features  that  one  focusses  on.
                  Furthermore, the marginal distribution of feature that characterizes a cluster
                  may be heterogeneous, e.g., Gaussian, Poisson or multinomial. To cope with
                  these  challenges  in  big  data  analysis,  we  developed  a  novel  multiple  co-
                  clustering method. Our method is based on nonparametric Bayesian mixture
                  models in which features are optimally partitioned for each cluster solution.
                  This feature partition works as feature selection for a particular cluster solution,
                  screening  out  irrelevant  features.  For  mixture  components,  we  assume
                  Gaussian, Poisson or multinomial distributions (pre-specified, but the mixing
                  of  these  different  types  in  data  is  allowed).  We  present  the  theoretical
                  foundation of our method, and show how our method works on real data. The
                  demonstration data is based on our recent study on identification of subtypes
                  of  depressive  disorder  using  high-dimensional  data  of  different  modalities
                  such as functional Magnetic Resonance Imaging (fMRI), clinical questionnaire
                  scores, and genetic polymorphism.

                  Keywords
                  Multi-view clustering; Mixture models; Feature selection; MRI

                  1.  Introduction
                      We consider a clustering problem for a data matrix that consists of objects
                  (or  subjects)  in  rows  and  features  (variables,  or  attributes)  in  columns.
                  Clustering objects based on the data matrix is a basic data mining approach,
                  which groups objects with similar patterns of distribution. As an extension of
                  conventional  clustering,  a  co-clustering  model  has  been  proposed,  which
                  captures not only object cluster structure, but also feature cluster structure
                  (Lazzeroni & Owen, 2002; Gu & Zhou, 2009; Madeira & Oliveira, 2004). In the
                  present paper, we focus on a specific type of co-clustering, so called ‘check


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