The Recursive Record Semantics of Objects Revisited

In a call-by-value language, representing objects as recursive records requires using an unsafe fixpoint. We design, for a core language including extensible records, a type system which rules out unsafe recursion and still supports the reconstruction of a principal type. We illustrate the expressive power of this language with respect to object-oriented programming by introducing a sub-language for «mixin-based» programming

Localization in Noetherian rings

This monograph first published in 1986 is a reasonably self-contained account of a large part of the theory of non-commutative Noetherian rings

Some Investigations Related to Gradients for Aircraft Parameter Estimation

This report describes the implementation of the Modified Newton Raphson with Estimated Sensitivities (MNRES) for gradient computations of the output error method. This method of gradient computation was tested on a range of aircraft models and its performance compared with the well known Modified Newton Raphson (MNR) method using finite differences. The results of this study are reported here. The finite difference method was also compared with exact sensitivities computed for a linear aircraft model. The convergence behaviour of the MNR methods is sensitive to the quality of the gradient information. It was found that when there were convergence problems in the MNR methods, the Levenberg- Marquardt method performed better