18 Mar. 14:00 Valeria Vitelli (University of Oslo, Norway)

If you are interested in attending the webinar, please contact the seminar organiser in advance.
Seminar organiser: Kalliopi Mylona
kalliopi.mylona@kcl.ac.uk

Title: The Bayesian Mallows model from preference learning to rank-based genomic data integration, with some recent advances

Abstract: The use of ranks in genomics is naturally linked to the underlying biological question, since one is often interested in overly-expressed genes in a given pathology. Moreover, ranks are insensitive to heterogeneity in the measurement scales, and more robust to outliers and measurement error. We propose to use a Bayesian Mallows model for ranks, able to both produce estimates of the consensus ranking of the genes shared among samples, and to fill-in missing data information. Interestingly, the model has already been fruitfully applied in other contexts, such as recommender systems, where it has proved to be useful for learning individualised preferences of the users, useful for providing personalized suggestions. Both when used in the context of genomics studies, and in user-oriented applications, posterior distributions of the unknowns are particularly relevant, since these can provide an evaluation of the uncertainty associated to the estimates, and thus of the reliability of the results.

I will present a statistical model, the Bayesian Mallows ranking model, which works well in these situations, and which is able of flexibly handling quite different kinds of data. The Bayesian paradigm allows for a fully probabilistic analysis, and it easily handles missing data and cluster estimation via augmentation procedures. I will briefly review some relevant case studies to show the method's potentialities in the variety of situations in which we applied it, from genomic data integration to recommender systems. I will then conclude with a brief teaser on the most recent advancements and extensions.
________________________________
If you are interested in attending the webinar, please contact the seminar organiser in advance.
Seminar organiser: Kalliopi Mylona
kalliopi.mylona@kcl.ac.uk

Valeria Vitellia