His research expertise lies mainly in the modelling and analysis of biomedical, pharmacokinetic and biological processes. Much of the emphasis of this work has been on compartmental modelling and the application of techniques in system dynamics, non- linear systems, control theory and system identification. He has particular expertise in structural identifiability analysis, that is determining whether the parameters of a postulated model can be estimated if perfect data are available. Such analysis is an important prerequisite for system identification, parameter estimation and experiment design. Over recent years his research has centred on techniques for analysing the structural identifiability of non-linear systems and computer algebra/symbolic computation packages have proved invaluable tools in this context. He also has an interest in the robust simulation of highly stiff systems.
His research has been performed in close collaboration with academic, industrial and hospital-based research groups and funding has been received from a variety of research councils including the EPSRC, the BBSRC and the MRC. He was one of the recipients of the 2001 Snell Premium from the Institute of Electrical Engineers for a paper on wavelet analysis of heart rate variability and its application in the detection of sleep apnoea.
He is leader of the Gait (Motion Analysis) Lab, which aims to develop finer scale musculoskeletal models of human motion than are currently used in practise.