Research Interests

Below is a brief description of each of several areas of research that I am currently involved in. In no particular order these can be losely described as Bayesian and MCMC Methodology, Extreme Value Theory and Biostatistics.

Potential PhD students are advised to contact me to discuss possible areas of research.

BAYESIAN AND MCMC METHODOLOGY

Over the past twenty years Bayesian statistics has seen a resurgence in popularity largely due to the development of stochastic methodologies capable of numerically approximating the necessary integrals. A popular set of such methods are based on the construction of a Markov chain with a stationary distribution proportional to the posterior distribution of interest. Current interest is concerned with the development of more efficient and more automatic samplers. The ultimate aim is the determination of algorithms that, given the required stationary distribution, will automatically determine the most efficient methods of traversing both within and between model spaces. Samplers that can additionally perform such simulations on posterior distributions constructed from possibly improper priors are another important goal.

EXTREME VALUE THEORY

Extreme value theory, as the name suggests, is concerned with the analysis of the extreme levels of processes. Such processes where a study of the very high level can be found in many areas. Some of these might include the environment (extreme rainfall, wind speeds, tidal surges, droughts, hurricaines, earthquakes etc.), finance (extremely high or low log daily returns, risk analysis etc.) and physical manufacturing processes (size of impurities in steel making). The analysis of such processes is motivated by a set of models that hold asymptotically, in analogue to the central limit theorem. While these models are useful in quite general situations, there is considerable room for the development of more flexible frameworks. There is particular scope for development under a Bayesian framework, especially where prediction of the process under study is of central interest. The above image records the size of some of the rocks moved by flash floods, caused by extreme levels of rainfall, in a storm over Vargas (in the central coast of Venezuela) in December 1999.

BIOSTATISTICS

Due to substantial leaps in technology over recent years, the biological sciences are now routinely generating large amounts of genetic-based data. The types of data being generated requires that novel methodology be developed for their analysis. One such illustration is the rapidly expanding field of microarray analysis, whereby ''snap-shots'' of an individuals gene activity levels can be captured through time or under different experimental settings (see image). These data are typically high dimensional (many thousands of genes), but low in the number of available replecations, and therefore require the development of new techniques to analyse them. Other application areas include disease/trait gene mapping on genealogies, DNA-based analysis of phylogenetic trees and issues involved in genetical database searches.