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Title: Continuous automata : bridging the gap between discrete and continuous time system models
Author: Westhead, Martin D.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1998
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The principal use of models in design and maintenance of a system is fundamental to the engineering methodology. As the complexity and sophistication of systems increase so do the demands on the system models required to design them. In particular, the design of agent systems situated in the real world, such as robots, will require design models capable of expressing discrete and continuous changes of system parameters. Such systems are referred to as mode-switching, or hybrid systems. This thesis investigates ways in which time is represented in automata system models with discrete and continuously changing parameters. Existing automata approaches to hybrid modelling rely on describing continuous change at a sequence of points in time. In such approaches the time that elapses between each point is chosen nondeterministically in order to ensure that the model does not over step a discrete change. In contrast, the new approach this thesis proposes describes continuous change by a continuum of points which can naturally and deterministically capture such change. The main contribution of this work is the derivation of a limiting process which provides a theoretical foundation for this new approach. It not only provides a link between discrete and continuous time representations, but also provides a basis for deciding which continuous time representations are theoretically sound. The resulting formalism, the Continuous I/O machine, is demonstrated to be comparable to Hybrid Automata in expressibility. The conclusion of this work is that it is possible to define an automata model that describes a continuum of events and that this can be effectively used to model mode-switching physical systems. An investigation of potential theoretical benefits lies outside the scope of this thesis, however I argue that it provides a more natural, and elegant way to describe such systems than existing models.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available