published_or_final_version / Mathematics / Master / Master of Philosophy

In this paper we consider three topics in reliability and maintenance. Their common feature is the explicit consideration of interdependence, either amongst components within a machine, amongst stages in a logistics chain, or amongst machines sharing maintenance facilities. Chapter 1 examines measures of the contribution of a component towards a system's reliability; these measures include structural importance, marginal reliability importance, joint reliability importance, and link importance. We review these different measures and examine how they relate to each other. We show that some structural results previously derived for independent components continue to hold for associated components. We then propose extensions to each importance measure to cover components which have two failure modes rather than the conventional one, and show that these extensions largely retain the properties of the original definitions. Chapter 2 examines a system containing one machine subject to random failure, for which we wish to determine a maintenance policy and a spare ordering policy. We consider the solvability and desirability of jointly optimizing these two traditionally separate policies. We discuss why the general form of the problem is intractable and show how it might be approached using bounds and heuristic policies; more importantly, we examine several special cases which are more tractable. Particular attention is paid to systems which contain only one spare at a time; we show that these systems have some convexity properties which facilitate cost minimization. We subsequently consider systems which allow more than one spare, but make use of other restrictions or assumptions to simplify analysis. Chapter 3 examines how to coordinate maintenance for machines sharing repair facilities, a task which is commonly called the machine repairman problem. Existing studies of this problem make the restrictive assumption that repairs are performed only after machine failure; our work extends the machine repairman model by allowing preventive repair. We derive analytical results for a single critical age repair policy, and then use numerical studies to investigate other heuristic policies which can improve the system's cost effectiveness.

Occupational safety is gaining a higher profile across all sectors of the United Kingdom's economy. This is largely a result of developments in legislation, increased indemnity insurance and the successful promotion of safety practice through the work of the Health and Safety Executive and the writings of health and safety professionals. This thesis has been undertaken to develop a dynamic simulation model of occupational safety strategy using system dynamics and empirically test it in an industrial setting. The work also seeks to capture a measure of the suitability of the occupational safety model as a pedagogic and decision-making aid. The results show that the occupational safety model was successfully developed, tested and evaluated within a firm. A range of alternative scenarios which suggested reductions in accidents at work and the costs of running a safety management system were predicted by the model. The relevant managers of the industrial enterprise were able to appreciate the model's capability for acting as an instruction tool to improve safety in the workplace. They were also able to judge the usefulness of the model for reducing occupational accidents and their related costs.

Thesis (Ph. D.)--Faculty of Law, University of Sydney, 2006. / Title from title screen (viewed 13th February, 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Law, University of Sydney. Degree awarded 2006. Includes bibliographical references. Also available in print form.

Thesis (Ph. D.)--University of North Texas, May, 2008. / Title from title page display. Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 290-313).

Thesis (M. Phil.)--University of Hong Kong, 1995. / Includes bibliographical references (leaves 83-86).

Thesis (D. Min.)--Gordon-Conwell Theological Seminary, Charlotte, NC, 2002. / Abstract and vita. Includes bibliographical references (leaves 216-224).

Thesis--Bonn. / Vita. Includes bibliographical references (p. 334-353).

Thesis (D. Min.)--Gordon-Conwell Theological Seminary, 2005. / Abstract and vita. Includes bibliographical references (leaves 189-200).