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Department of Mathematical Sciences

Seminar Archives

On this page you can find information about seminars in this and previous academic years, where available on the database.

Stats4Grads: Calibrating the Universe: an Uncertainty Analysis for a Galaxy Formation Simulation

Presented by Dr Ian Vernon, Durham University

8 October 2008 14:15 in CM105

Abstract: Many scientific areas now employ large physical computer simulations in order to understand complex real world systems. Such simulations contain a large number of input and output parameters and this leads to several problems of interest. A subset of the outputs can be compared with observed data of the real system, and a natural question to ask is: which choices of input parameters to the model will give rise to `acceptable' matches between the outputs and the data. This is known as Calibration and is one of the most important problems when dealing with models of this size and complexity.

I will describe a version of Calibration known as History Matching in the context of a Galaxy Formation simulation that attempts to model the evolution of one million galaxies from the beginning of the Universe until the present day. I will describe the process of Emulation (the statistical modelling of a deterministic function) and the method of History Matching via an Implausibility measure. Communicating the results of a successful Calibration is also a non-trivial matter as this involves describing a complex shape in a high-dimensional space, so various visualisation issues and techniques will also be discussed.

This seminar is for Postgraduate Students and Postdoctoral Researchers only

Contact thomai.tsiftsi(@) for more information

See the Stats4Grads page for more details about this series.