Please use this identifier to cite or link to this item: http://hdl.handle.net/10419/95281
Authors: 
Altomare, Davide
Consonni, Guido
La Rocca, Luca
Year of Publication: 
2011
Series/Report no.: 
Quaderni di Dipartimento 140
Abstract: 
Directed Acyclic Graphical (DAG) models are increasingly employed in the study of physical and biological systems, where directed edges between vertices are used to model direct influences between variables. Identifying the graph from data is a challenging endeavor, which can be more reasonably tackled if the variables are assumed to satisfy a given ordering; in this case, we simply have to estimate the presence or absence of each possible edge, whose direction is established by the ordering of the variables. We propose an objective Bayesian methodology for model search over the space of Gaussian DAG models, which only requires default non-local priors as inputs. Priors of this kind are especially suited to learn sparse graphs, because they allow a faster learning rate, relative to ordinary local priors, when the true unknown sampling distribution belongs to a simple model. We implement an efficient stochastic search algorithm, which deals effectively with data sets having sample size smaller than the number of variables. We apply our method to a variety of simulated and real data sets.
Subjects: 
Fractional Bayes factor
High-dimensional sparse graph
Moment prior
Non-local prior
Objective Bayes
Pathway based prior
Regulatory network
Stochastic search
Structural learning
Document Type: 
Working Paper

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