Maintaining accessibility to and understanding of digital information over time is a complex challenge that often requires contributions and interventions from a variety of individuals and organizations. The processes of preservation planning and evaluation are fundamentally implicit and share similar complexity. Both demand comprehensive knowledge and understanding of every aspect of to-be-preserved content and the contexts within which preservation is undertaken. Consequently, means are required for the identification, documentation and association of those properties of data, representation and management mechanisms that in combination lend value, facilitate interaction and influence the preservation process. These properties may be almost limitless in terms of diversity, but are integral to the establishment of classes of risk exposure, and the planning and deployment of appropriate preservation strategies. We explore several research objectives within the course of this thesis. Our main objective is the conception of an ontology for risk management of digital collections. Incorporated within this are our aims to survey the contexts within which preservation has been undertaken successfully, the development of an appropriate methodology for risk management, the evaluation of existing preservation evaluation approaches and metrics, the structuring of best practice knowledge and lastly the demonstration of a range of tools that utilise our findings. We describe a mixed methodology that uses interview and survey, extensive content analysis, practical case study and iterative software and ontology development. We build on a robust foundation, the development of the Digital Repository Audit Method Based on Risk Assessment. We summarise the extent of the challenge facing the digital preservation community (and by extension users and creators of digital materials from many disciplines and operational contexts) and present the case for a comprehensive and extensible knowledge base of best practice. These challenges are manifested in the scale of data growth, the increasing complexity and the increasing onus on communities with no formal training to offer assurances of data management and sustainability. These collectively imply a challenge that demands an intuitive and adaptable means of evaluating digital preservation efforts. The need for individuals and organisations to validate the legitimacy of their own efforts is particularly prioritised. We introduce our approach, based on risk management. Risk is an expression of the likelihood of a negative outcome, and an expression of the impact of such an occurrence. We describe how risk management may be considered synonymous with preservation activity, a persistent effort to negate the dangers posed to information availability, usability and sustainability. Risk can be characterised according to associated goals, activities, responsibilities and policies in terms of both their manifestation and mitigation. They have the capacity to be deconstructed into their atomic units and responsibility for their resolution delegated appropriately. We continue to describe how the manifestation of risks typically spans an entire organisational environment, and as the focus of our analysis risk safeguards against omissions that may occur when pursuing functional, departmental or role-based assessment. We discuss the importance of relating risk-factors, through the risks themselves or associated system elements. To do so will yield the preservation best-practice knowledge base that is conspicuously lacking within the international digital preservation community. We present as research outcomes an encapsulation of preservation practice (and explicitly defined best practice) as a series of case studies, in turn distilled into atomic, related information elements. We conduct our analyses in the formal evaluation of memory institutions in the UK, US and continental Europe. Furthermore we showcase a series of applications that use the fruits of this research as their intellectual foundation. Finally we document our results in a range of technical reports and conference and journal articles. We present evidence of preservation approaches and infrastructures from a series of case studies conducted in a range of international preservation environments. We then aggregate this into a linked data structure entitled PORRO, an ontology relating preservation repository, object and risk characteristics, intended to support preservation decision making and evaluation. The methodology leading to this ontology is outlined, and lessons are exposed by revisiting legacy studies and exposing the resource and associated applications to evaluation by the digital preservation community.

The time-averaged Navier-Stokes' partial differential equations have been used in the mathematical modelling of fluid flow for steady, incompressible non-cavitating, high Reynolds number turbulence through an orifice plate. The model developed for orifice plates was based on a particular closed form turbulent model: the k-ε two equation model developed at Imperial College, London and embodied in the TEACH-T finite difference computer code. A basic model for axisymmetric flow through an orifice meter was developed by appropriate modification of the TEACH-T program to incorporate orifice plate geometry, upstream/downstream distances, Reynolds number, inlet velocity profile and the calculation of output quantities of interest such as discharge and pressure loss coefficients. The model vas tested for convergence and general adequacy on an orifice of diameter ratio β= .7 in a 4 inch pipe line and at a Reynolds number of 105. Quantitative tests were then conducted on thin orifice plates in the range .3 β .7. Results were compared with those from BSI 1042 for discharge coefficients (flange, D-D/2 and corner tappings) and published results for pressure loss coefficients. The results show that the discharge coefficients predictions are within 3% of experiment with very close agreement in the mid-range (β = .45). The pressure loss coefficients predictions are within 15" of experiment. Sensitivity tests were then conducted to see how these coefficients varied with such quantities as inlet velocity I profile, turbulence levels and orifice plate thickness. These results indicated that the orifice is relatively insensitive to velocity profiles (1/12 power law and uniform) and. turbulence levels. Also below a certain orifice plate thickness ratio the discharge coefficient is almost constant. It is concluded that such modelling can be a most valuable aid in understanding the behaviour of the orifice meter and similar devices. In particular this would aid in the design of novel flow meters based on the differential pressure principle. Extensive mathematical and computational details including the derivation of the k-t model equations from first principles are relegated to appendices. A source listing of the developed model is also provided in appendix G.

In this study an in depth investigation of successful competitive strategies for small to medium-sized enterprises (SMEs) is undertaken. The overall aim of this study is to analyse the strategic orientation of UK Manufacturing SMEs. In the process, it will test Porter’s (1980, 1985) theoretical framework of generic strategies and thus evaluate firms’ preferred strategic synthesis. It will, therefore, test the efficacy of the value chain and develop any specific pattern that relates to a combination strategy. The investigation of the above objectives is undertaken utilising a mixed research methodology with the purpose of examining the applicability of existing competitive strategy frameworks (phase 1) and testing a new theoretical framework that incorporates additional dimensions of strategy (phase 2). During phase 1, Porter’s framework is employed to investigate SMEs’ strategic orientation as a means to achieve sustainable competitive advantage. A semi-structured questionnaire is employed and the analysis is carried out by means of factor and cluster analysis to identify strategic variables currently employed by SMEs. During phase 2, the theoretical framework is operationalised to bridge the gap within the literature and existing empirical research. Its purpose is to identify forms of successful competitive strategies of UK MSMEs as they are formulated and implemented in firms’ value chain activities. The data was collected through a number of semi-structured interviews and the analysis was based on data categorisation. The findings indicate that Porter’s (1980) single generic strategies are not the best option for UK MSMEs for gaining competitive advantage and that the