A conceptual framework for uncertainty in software systems and its application to software architectures

The development and operation of a software system involve many aspects including processes, artefacts, infrastructure and environments. Most of these aspects are vulnerable to uncertainty. Thus, the identification, representation and management of uncertainty in software systems is important and will be of interest to many stakeholders in software systems. The hypothesis of this work is that such consideration would benefit from an underlying conceptual framework that allows stakeholders to characterise, analyse and mitigate uncertainties. This PhD proposes a framework to provide a generic foundation for the systematic and explicit consideration of uncertainty in software systems by consolidating and extending existing approaches to dealing with uncertainty, which are typically tailored to specific domains or artefacts. The thesis applies the framework to software architectures, which are fundamental in determining the structure, behaviour and qualities of software systems and are thus suited to serve as an exemplar artefact. The framework is evaluated using the software architectures of case studies from 3 different domains. The contributions of the research to the study of uncertainty in software systems include a literature review of approaches to managing uncertainty in software architecture, a review of existing work on uncertainty frameworks related to software systems, a conceptual framework for uncertainty in software systems, a conceptualisation of the workbench infrastructure as a basis for building an uncertainty consideration workbench of tools for representing uncertainty as part of software architecture descriptions, and an evaluation of the uncertainty framework using three software architecture case studies