**The Centre for Mathematical Sciences**** research seminars and events are listed below.**

The four main seminar series are in applied mathematics, pure mathematics, statistics and theoretical physics. Visit the centre's webpages for the latest seminar updates and information.

**Wednesday 16 October | Room 116, Rolle Building (15:00-16:00)**

**A Loss-Based Prior for Variable Selection in Linear Regression Methods**

- Speaker: Cristiano Villa (University of Kent)

Abstract: In this work we propose a novel model prior for variable selection in linear regression. The idea is to determine the prior mass by considering the worth of each of the regression models, given the number of possible covariates under consideration. The worth of a model consists of the information loss and the loss due to model complexity. While the information loss is determined objectively, the loss expression due to model complexity is flexible and, the penalty on model size can be even customized to include some prior knowledge. Some versions of the loss-based prior are proposed and compared empirically. Through simulation studies and real data analyses, we compare the proposed prior to the Scott and Berger prior, for non-informative scenarios, and with the Beta-Binomial prior, for informative scenarios.

Tuesday 22 October | Room 205, 2-5 Kirkby Place

**In situ container-less neutron scattering experiments on liquids and aqueous solutions: an overview on levitation techniques at Institute Laue Langevin (ILL)**

- Speaker: Viviana Cristiglio, ILL

**Wednesday 30 October |
Pigeon-holes and mustard seeds: Growing capacity to use data for society
**

- Speaker: Professor Deborah Ashby, Imperial College London

The Royal Statistical Society was founded to address social problems ‘through the collection and classification of facts’, leading to many developments in the collection of data, the development of methods for analysing them, and the development of statistics as a profession. Nearly 200 years later an explosion in computational power has led, in turn, to an explosion in data. We outline the challenges and the actions needed to exploit that data for the public good, and to address the step change in statistical skills and capacity development necessary to enable our vision of a world where data are at the heart of understanding and decision-making.

Contact yinghui.wei@plymouth.ac.uk for any queries.

**Wednesday 6 November | Colloquium - The Complex Dynamics of Faraday Pilot Waves: A Hydrodynamic Quantum Analogue **

- Speaker: Paul Milewski, Bath

Abstract: Faraday pilot waves are a newly discovered hydrodynamic structure that consists a bouncing droplet which creates, and is propelled by, a Faraday surface wave. These pilot waves can behave in extremely complex ways exhibiting a classical form of wave-particle duality, and result in dynamics mimicking quantum mechanics, including multiple quantisation, probabilistic particle distributions reminiscent of QM, diffraction and tunnelling. I will show some of this fascinating behaviour and will develop a surface wave-droplet fluid model that captures many of the features observed, and focus on rationalising the emergence of the statistics of complex states.

Contact raphael.stuhlmeier@plymouth.ac.uk for any queries.

**Wednesday 13 November | The Universal Route to Rogue Waves via Instanton Theory**

- Speaker: Tobias Grafke (Warwick)

Abstract: In stochastic systems, extreme events are known to be described by “instantons”, saddle point configurations of the action of the associated stochastic field theory. In this talk, Tobias will present experimental evidence of a hydrodynamic instanton in a real world fluid system: A 270m wave channel experiment in Norway. The experiment attempts to model conditions on the ocean in order to observe so-called rogue waves, realisations of extreme ocean surface elevation out of relatively calm surroundings. These rogue waves are also observed in the ocean, where they are rare and hard to predict but pose significant danger to naval vessels. We show that the instanton approach, which is rigorously grounded in large deviation theory, offers a unified description of rogue waves in the water tank, covering the entire range of parameters for deep water waves in the ocean. In particular, this approach allows for a unified description of both the predominantly linear and the highly nonlinear regimes, and is able to predict the experimental data in the tank regardless of the strength of the nonlinearity.