PhD ceremony: Mr. A. Abbruzzo, 11.00 uur, Academiegebouw, Broerstraat 5, Groningen
Dissertation: Graphical models for estimating dynamic networks
Promotor(s): prof. E.C. Wit, prof. A.M. Mineo
Faculty: Mathematics and Natural Sciences
Estimating dynamic networks from data is an active research area and it is one important direction in system biology. Estimating the structure of a network is about deciding the presence or absence of relationships between the nodes. Graphical models describe conditional independence relationships. Gaussian graphical models assume that the nodes follow a multivariate normal distribution. When Gaussian graphical models are applied in order to study large networks, they typically fail because the number of variables is much greater than the number of observations. Recently, penalized Gaussian graphical models have been proposed to estimate static networks in high-dimensional studies because of their statistical properties and computational tractability. We propose to use penalized Gaussian graphical models to estimate structured dynamic networks, for modeling slowly changing of dynamic networks, and to estimate particular structures such as scale-free dynamic networks in a small world setting. These models can be applied when estimating dynamic networks in high dimensional environments. When the underlying dynamic processes represented via binary, ordinal, count or otherwise non-Gaussian data, we propose to use the Gaussian copula for defining a general non-Gaussian graphical model. The Gaussian copula effectively transforms the data by means of marginal transformations or via latent Gaussian variables. This approach is very powerful and has the advantage of being able to deal with mixed types of variables of arbitrary distribution. The problem of estimating dynamic networks becomes even more challenging when latent or hidden variables are involved in larger systems. State-space models have been proposed in order to study dynamic networks with latent variables. We propose a penalized Gaussian graphical models to estimate dynamic networks with latent structures.
Bayu Jayawardhana has been appointed scientific director of DISC, the interuniversity research institute and graduate school that unites all university groups in the Netherlands that are active in systems and control theory and engineering. The...
Researchers Clemens Mayer and Danny Incarnato of the University of Groningen have been awarded an ERC Consolidator Grant.
Commissioned by the UG, photographer Eddo Hartmann made the series Collective Landscape about Laura Govers’ research.
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