Knowledge-based engineering for the scanning electron microscope

The dissertation is an account of the author's research into the analysis, design, and implementations of knowledge-based (expert) systems for applications in the field of scanning electron microscopy. The specific tasks of interest have been fault diagnosis and instrument control. This research represents the first utilisation of knowledge-based techniques within electron microscopy. The dissertation begins by providing background material on the scanning electron microscope and surveying the expert systems literature with regard to critical areas of system design. The target applications and the associated research objectives are next summarised. A set of novel algorithms for improving the microscope by enhanced automatic control of fundamental instrument parameters, namely tungsten filament saturation and alignment, are presented, and the area of automatic focus algorithms is reinvestigated. Research into the design and implementation of an expert system for microscope fault diagnosis, including mechanisms for interfacing the expert system to the Internet, is discussed. This is followed by a detailed presentation of the development of a knowledge-based approach to instrument control. The next segment of this dissertation concentrates upon theoretical issues arising from the preceding work. A proposal is made to classify network-aware expert systems, and the impact of the Internet and the World Wide Web upon such systems is discussed within this context. An analysis of the work is performed to indicate how the practical portions of the research may be generalised to other tasks within scanning electron microscopy and outwith to other scientific instruments.