Postgraduate Seminar: Edwards/Mitchell

3pm  Carslaw 157
Tuesday 20th October

Speaker: James Edwards

Title: Towards a mathematical understanding of group decision making

It is common for individuals belonging to a group to collaborate and reach a
collective decisions. Such collaboration need not be through language, for
example the actions of decision making individuals may influence those
around them, implicitly leading to a decision being made by the group.

Examples of this type of individual / group decision making include
elections and markets in human society, or foraging and house-hunting in
insect society.

I will discuss the problem and construct a model to investigate it. Using
the model I will show how surprisingly deep insights into group decision
making have been found.


Speaker: Lewis Mitchell

Title: An introduction to data assimilation and ensemble Kalman filtering

A fundamental problem in numerical weather prediction is how to  
estimate the current state of the atmosphere. With the number of  
observations available generally being orders of magnitude smaller  
than the model dimension, this is highly non-trivial. Data  
assimilation is a way of combining imperfect observations of a system  
with a numerical model to produce an estimate of the state of the  
system.

In this talk, we will introduce one of the state-of-the art tools in  
data assimilation, the ensemble Kalman filter, and show how it arises  
from Bayesian estimation and/or variational approaches. We will  
illustrate its use through some simple climatic models.