System Modelling for Requirements Engineering

Abstract

Art and science have their meeting point in method. Edward Bulwer-Lytton, poet, 1803-1873 AD 3.1 Introduction System modelling supports the analysis and design process by introducing a degree of formality into the way systems are defined. During system development it is often the case that pictures are used to help visualize some aspects of the development. Modelling provides a way of formalising these representations, through diagrams, by not only defining a standard syntax, but also providing a medium for understanding and communicating the ideas associated with system development. The art of modelling is arguably the most creative aspect of the work of the systems engineer. There is no "right" solution and models will evolve through various stages of system development. Models are most often represented visually and the information is therefore represented through connected diagrams. New methods such as object-orientation have advanced the concept of modelling, however most approaches are also based on the principles used and tested over time. A model is an abstraction of a system that deliberately focuses on some aspects of a system to the exclusion of others. Abstraction is, in this sense, avoidance of distraction-ignoring those details that, although important, are not relevant to a particular model. The advantage of this is that smaller amounts of related information can be collected, processed, organised and analysed, applying various specific techniques pertinent to the aspects under study. Where a large amount of complex information has to be managed, modelling provides a means of zooming in, collecting together subsets of the data for a 57