This talk describes progress at understanding the properties of the nucleon and its excitations from lattice QCD. I begin with a review of recent lattice results for the lowest-lying states of the excited baryon spectrum. The need to approach physical values of the light quark masses is emphasized, enabling the effects of the pion cloud to be revealed. I then outline the development of techniques that will enable the extraction of the masses of the higher resonances. I will describe how such calculations provide insight into the structure of the hadrons, and enable comparison both with experiment, and with QCD-inspired pictures of hadron structure, such as calculations in the limit of large N{sub c}.

The existing theory of consistency-based diagnosis and its implementations have proven successful in a number of technical applications. However, they turn out to be inherently limited to a very specific class of systems to be diagnosed: they are tailored for artifacts consisting of components in a fixed structure and they are aimed at a particular kind of diagnosis and repair, namely failing components and their replacement. This thesis presents a generalization of the theory of consistency-based diagnosis, applicable to a much wider class of systems and diagnosis problems, while preserving the approach based on first principles and the core of the existing logical foundations. The central contributions are a logical reconstruction of a process-oriented modelling paradigm, a concise characterization of solutions to the diagnostic tasks of situation assessment and therapy recognition, and an algorithmic approach to computing the specified solutions. Finally, an implemented prototype, the generalized diagnosis engine (G+DE) and several extended application examples are presented.