Co-clustering Numerical Data under User-defined Constraints
Résumé
In the generic setting of objects x attributes matrix data
analysis, co-clustering appears as an interesting unsupervized data
mining method. A co-clustering task provides a bi-partition made of
co-clusters: each co-cluster is a group of objects associated to a
group of attributes and these associations can support expert
interpretations. Many constrained clustering algorithms have been
proposed to exploit the domain knowledge and to improve partition
relevancy in the mono-dimensional clustering case (e.g., using the
must-link and cannot-link constraints on one of the two dimensions).
Here, we consider constrained co-clustering not only for extended
must-link and cannot-link constraints (i.e., both objects and
attributes can be involved), but also for interval constraints that
enforce properties of co-clusters when considering ordered domains.
We describe an iterative co-clustering algorithm which exploits
user-defined constraints while minimizing a given objective
function. Thanks to a generic setting, we emphasize that different
objective functions can be used. The added value of our approach is
demonstrated on both synthetic and real data. Among others, several
experiments illustrate the practical impact of this original
co-clustering setting in the context of gene expression data
analysis, and in an original application to a protein motif discovery problem.