Inverse methods and modelling.
Thesis DisciplineElectrical Engineering
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Three applications of inverse methods are considered, The theoretical bases of the major inverse scattering techniques used to the interior of penetrable bodies are reviewed X-ray crystallography is used to image the molecular structure of crystals. Two models of the DNA molecule are analysed on the basis of the X-ray diffraction data. The two models are the widely accepted "double helix" and the recently proposed "side-by-side". It is shown that the side-by-side model fits the diffraction data at least as well as the double helix. A stereochemical analysis shows that the side-by-side model is also stereochemically acceptable. Current methods. for imaging regions of variable refractive index are useful only for weak inhomogeneities, A time domain method for imaging one-dimensional regions of arbitrary variation in refractive index is outlined. It is shown that this method may be applied to. Branched transmission line networks. These techniques are applied to both simulated and measured data. Physiological and clinical aspects of cardiac arrhythmias are reviewed. A modelling approach to the inverse problem of cardiac arrhythmia diagnosis is outlined. The important variables describing cardiac conduction are identified and used as the basis of an interactive computer model to assist in arrhythmia diagnosis. It is shown that the model can simulate realistic quantitative rhythms, Methods of processing patients' clinical data to identify the model parameters are described. Examples of the use of the model to simulate two patients' arrhythmias are presented.