Tuesday, November 19, 2002
8:30 am - 12:00 noon

Viewpoint Analysis and Requirements Engineering

Bashar Nuseibeh
Computing Dept., The Open University, UK
Systems Engineering Studios, Imperial College, UK

Steve Easterbrook
Department of Computer Science
University of Toronto, Canada

Abstract

Modelling and analysis of software systems requirements can be difficult because the available information is invariably inconsistent and incomplete, especially in the early phases of the development lifecycle. Different stakeholders often have very different perspectives on the requirements. They use different vocabulary, they talk about different aspects of the problem, they have different ways of structuring their descriptions, and they may have conflicting goals.

Viewpoint Analysis offers a practical solution to these challenges. A viewpoint combines the idea of a view (or perspective) of a problem domain together with an owner for that view. Inconsistencies may arise in the overlaps among viewpoints, permitting local reasoning within each viewpoint. Inter-viewpoint consistency checking is supported using a set of heuristic rules. Key advantages of this approach include stakeholder buy-in and traceability, flexible collaboration, and richer modelling structures.

This tutorial will begin with a state-of-the-art survey of viewpoint analysis methods. We will then show how viewpoint analysis can be used to exploit the natural structure of the requirements modelling process, so that each viewpoint becomes a self contained-specification tool. Using a case study, we will show how consistency checking among viewpoints is handled, and show how fine-grained process models can be used to control the application of consistency rules. We will conclude with a brief look at recent research on inconsistency management, including work on non-classical logics that permit formal analysis of inconsistent sets of viewpoints.

Presenter Biographies

Bashar Nuseibeh is Professor of Computing and Director of Research at The Open University, and Visiting Research Fellow at Imperial College, London. Previously, he was a Reader at Imperial College, Director of its Centre for Systems Requirements Engineering, and Head of its Software Engineering Laboratory. His research interests are in software requirements engineering and design, software process modelling and technology, and technology transfer. He has published over 75 refereed papers and consulted widely in these areas, working with organisations such as NASA, the UK National Air Traffic Services, Texas Instruments, and Philips Research Labs.

He is Editor-in-Chief of the Automated Software Engineering Journal published by Kluwer, a member of the Editorial Board of the Requirements Engineering Journal published by Springer, and Chairman of the British Computer Society's Requirements Engineering Specialist Group. He was Programme Co-Chair of the 13th IEEE Conference on Automated Software Engineering in the US, and Programme Chair of the 5th IEEE International Symposium on Requirements Engineering (RE'01) in Canada.

He holds an MSc and PhD in Software Engineering from Imperial College, and a First Class Honours BSc in Computer Systems Engineering from the University of Sussex, UK. He is a Member of the British Computer Society (BCS), the Institution of Electrical Engineers, IFIP WG 2.9, and is a Chartered Engineer (C.Eng.).

Steve Easterbrook is an associate professor in the Department of Computer Science, University of Toronto, Canada, where he teaches courses in Software Engineering and Requirements Engineering, and conducts research into requirements modeling, management of inconsistency in specifications, requirements negotiation, and multi-valued model checking. Dr Easterbrook received his B.Sc. in Computer Science from the University of York, UK, in 1986, and his Ph.D. in Software Engineering from Imperial College London in 1991. He was a lecturer in computer science and artificial intelligence at the University of Sussex in the UK for five years. He was then appointed research lead at the NASA Independent Verification and Validation Facility in West Virginia, where he conducted applied research into requirements engineering, software V&V, and formal methods, as part of a NASA-wide program of research and development in software engineering, aimed at improving the current state of practice in the development and assurance of high-risk, high assurance software systems. He moved to Toronto in 1999. He has published over 40 papers in the field of requirements engineering, and has edited a book on Computer Supported Collaborative Work. He has served on the program committee for the international symposia and conferences in Requirements Engineering, as well a number of other international conferences. In 2001, he served as General Chair for the International Symposium on Requirements Engineering, which was held in Toronto.