Active object-oriented databases: Extensions and application to process automation and control

Research carried out for this dissertation examines important problems arising from the extension of object-oriented databases (OODBs) to provide active rule capability, solves these problems, and demonstrates the application of active database technology for semi-conductor process automation and control. Specifically, this dissertation makes three main contributions.; Though, inheritance and overriding are fundamental features of object-oriented systems, current active OODB systems have overlooked the provision of these features. This dissertation develops a formal object model which establishes a clear relationship between the active and passive parts of the database schema, and extends support for inheritance, overriding and syntactic compatibility to active rules. This model provides a formal basis for extending active OODB systems to provide support for active rule inheritance and overriding.; Automated execution and control of a (manufacturing) process requires support for automated fault detection and automated modification of process settings. Leveraging off characteristics common to process specification schemas in many domains, extensions to active OODBs are proposed to facilitate specification and enactment of processes. These extensions, which provide a novel mechanism for the specification of modular, reusable and maintainable manufacturing processes, include: (1) higher-level object modeling constructs for representing process structure via the passive schema, and control knowledge by using active rules, (2) techniques for defining active rules that are maintainable and tractable, and (3) extending inheritance support for process definitions.; Using the proposed extensions a prototype controller, called the Active Controller, has been implemented for application to semiconductor manufacturing using the Ode active OODB system. The process is specified by an object-oriented data structure, with the multi-step control knowledge specified in terms of active rules that carry out control by modifying the process structure whenever the need for control is detected. The Active Controller provides multi-step control in an adaptable and domain-independent manner. Additionally, the development of the Active Controller has provided a vehicle for gaining much-needed experience in developing active database applications, and for applying and validating the extensions presented in this dissertation.