For the last few years, the amount of data has significantly increased in the companies. It is the reason why data analysis methods have to evolve to meet new demands. In this article, we introduce a practical analysis of a large database from a telecommunication operator. The problem is to segment a territory and characterize the retrieved areas owing to their inhabitant behavior in terms of mobile telephony. We have call detail records collected during five months in France. We propose a two stages analysis. The first one aims at grouping source antennas which originating calls are similarly distributed on target antennas and conversely for target antenna w.r.t. source antenna. A geographic projection of the data is used to display the results on a map of France. The second stage discretizes the time into periods between which we note changes in distributions of calls emerging from the clusters of source antennas. This enables an analysis of temporal changes of inhabitants behavior in every area of the country.
In addition to the diversity of structures that can be inferred from the network, co-clustering approaches are also able to deal with continuous variables @cite_21 , @cite_14 . Blocks are extracted from the data that yields a discretization of the continuous variables. For a further analysis, we are able to track temporal patterns: the source antennas are still the rows in the data matrix while the columns now model the time.
@cite_14 @cite_21
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In this paper, we present a novel way of analyzing and summarizing a collection of curves, based on piecewise constant density estimation. The curves are partitioned into clusters, and the dimensions of the curves points are discretized into intervals. The cross-product of these univariate partitions forms a data grid of cells, which represents a nonparametric estimator of the joint density of the curves and point dimensions. The best model is selected using a Bayesian model selection approach and retrieved using combinatorial optimization algorithms. The proposed method requires no parameter setting and makes no assumption regarding the curves; beyond functional data, it can be applied to distributional data. The practical interest of the approach for functional data and distributional data exploratory analysis is presented on two real world datasets. The co-clustering consists in reorganizing a data matrix into homogeneous blocks by considering simultaneously the sets of rows and columns. Setting this aim in model-based clustering, adapted block latent models were proposed for binary data and co-occurrence matrix. Regarding continuous data, the latent block model is not appropriated in many cases. As non-negative matrix factorization, it treats symmetrically the two sets, and the estimation of associated parameters requires a variational approximation. In this paper we focus on continuous data matrix without restriction to non negative matrix. We propose a parsimonious mixture model allowing to overcome the limits of the latent block model.