Kerrie Mengersen, Queensland University of Technology (Australia)

Chairperson: David Conesa, Universitat de Valencia (Spain)

Title: Sloppy models: unveiling parameter uncertainty in mathematical models

Abstract:

In this presentation, I will discuss a Bayesian approach to assessing the sensitivity of model outputs to changes in parameter values in mathematical models, constrained by the combination of prior beliefs and data. The approach identifies stiff parameter combinations that strongly affect the quality of the model-data fit while simultaneously revealing which of these key parameter combinations are informed primarily from the data or are also substantively influenced by the priors. These stiff parameter combinations can uncover controlling mechanisms underlying the system being modeled and guide future experiments for improved parameter inference. The focus of the discussion will be on the very common context in complex systems where the amount and quality of data are low compared to the number of model parameters to be collectively estimated. The approach will be illustrated with applications in biochemistry, ecology, and cardiac electrophysiology.

This work is joint with Gloria Monsalve-Bravo (lead author), Brodie Lawson, Christopher Drovandi, Kevin Burrage, Kevin Brown, Christopher Baker, Sarah Vollert, Eve McDonald-Madden and Matthew Adams.

The full paper is available as an arXiv preprint arXiv:2203.15184

Pere Puig, Universidad Autónoma de Barcelona (Spain)

Chairperson: Carmen Armero, Universitat de Valencia (Spain)

Title: I've been irradiated!! What is the total amount of radiation I've re- ceived?

Abstract:

In the event of a radiation accident, biological dosimetry is critical for determining the radiation dose received by an exposed individual in a timely way. The dose is estimated by calculating the amount of damage caused by radiation at the cellular level, such as by counting the number of chromosome aberrations like dicentrics micronuclei, or translocations. The theory of count data distributions is critical for achieving this goal. In this talk, we will introduce the standard statistical methodology for dose estimation described in the International Atomic Energy Agency's manual (IAEA, 2011), as well as summarise recent research led by our team. We will present models based on compound Poisson processes that are suitable for describing high-LET radiation exposures such as those seen in the Fukushima accident, zero-inated and mixed Poisson models for partial and heterogeneous exposures, and weighted Poisson models for integrating low and high doses.