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Electronic publication; full text available in PDF format; abstract in HTML format. Electronic reproduction.[Australia] :Australian Digital Theses Program,2001.

Thesis (Ph.D.) -- University of Adelaide, Dept. of Computer Science, 2000. / Bibliography: leaves 265-280.

Thesis (Ph.D.) -- University of Adelaide, Dept. of Computer Science, 2000. / Also available in a print form.

Bibliography: leaves 265-280.

As the use of computer systems becomes more and more widespread in applications that demand high levels of dependability, these applications themselves are growing in complexity in a rapid rate, especially in the areas that require concurrent and distributed computing. Such complex systems are very prone to faults and errors. No matter how rigorously fault avoidance and fault removal techniques are applied, software design faults often remain in systems when they are delivered to the customers. In fact, residual software faults are becoming the significant underlying cause of system failures and the lack of dependability. There is tremendous need for systematic techniques for building dependable software, including the fault tolerance techniques that ensure software-based systems to operate dependably even when potential faults are present. However, although there has been a large amount of research in the area of fault-tolerant software, existing techniques are not yet sufficiently mature as a practical engineering discipline for realistic applications. In particular, they are often inadequate when applied to highly concurrent and distributed software. This thesis develops new techniques for building fault-tolerant software, addresses the problem of achieving high levels of dependability in concurrent and distributed object systems, and studies system-level support for implementing dependable software. Two schemes are developed - the t/(n-l)-VP approach is aimed at increasing software reliability and controlling additional complexity, while the SCOP approach presents an adaptive way of dynamically adjusting software reliability and efficiency aspects. As a more general framework for constructing dependable concurrent and distributed software, the Coordinated Atomic (CA) Action scheme is examined thoroughly. Key properties of CA actions are formalized, conceptual model and mechanisms for handling application level exceptions are devised, and object-based diversity techniques are introduced to cope with potential software faults. These three schemes are evaluated analytically and validated by controlled experiments. System-level support is also addressed with a multi-level system architecture. An architectural pattern for implementing fault-tolerant objects is documented in detail to capture existing solutions and our previous experience. An industrial safety-critical application, the Fault-Tolerant Production Cell, is used as a case study to examine most of the concepts and techniques developed in this research.

Experiential learning has been empirically confirmed to enhance performance of project organisations. This research investigates the literature and included field surveys to get insights into the barriers (and by default any enablers) relating to project related knowledge transfer in project orientated organisations. It seeks to explore the reality and perceptions related to experiential learning within an international group of organisations to confirm expected obstacles to learning.The research follows a quantitative approach in the form of a field survey and includes qualitative insights gained from a secondary data review. It seeks to test the validity of propositions articulating suspected barriers to learning as it is experienced or perceived to exist within the selected sample of organisations.This study is unique as, although it build on previous research, it introduces a new dimension in that experiential learning aspects as experienced by international organisations are measured simultaneously with conditions within related local organisations. The results confirmed a similar outcome between the two groups in terms of the research propositions and must be used by project orientated organisations to create management awareness in terms of the reality of specific barriers so as to guide implementation of suitable corrective measures. / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted

An essential motivation behind concurrent object-oriented systems is to exploit the software modularity and reuse potential of object-oriented features in the development of concurrent systems. However, the marriage between the two disciplines has not been a happy one. In this work we propose a model that reduces the problems associated with introducing concurrency into object-oriented languages. We explore techniques for reasoning about synchronisation requirements in composite object systems operating in a concurrent environment. Furthermore we investigate safe locking strategies, where the locks may be distributed over the components of the system and identify conditions for such locks to be non-redundant. Through the recognition of a Galois connection, we achieve an elegant mathematical characterisation of the lock-distribution problem, which allows us to identify efficient strategies and tools for assisting developers with lock selection.