Viewpoint Specification using Formal Methods
Viewpoint Specification using Formal Methods
Howard Bowman
Specification by viewpoints is widely advocated as a useful
method for dealing with the complexity of large systems.
Each viewpoint describes an aspect (rather than a
component or module) of the envisaged system, using a language
most suited to the viewpoint at hand. A
consequence of adopting such an approach is that descriptions of
the same or related entities can appear in different
viewpoints and must coexist. Thus, consistency of specifications
across viewpoints becomes a central issue.
I have worked on this topic with a number of other people, in particular,
Eerke Boiten,
John Derrick,
Peter Linington, and
Maarten Steen. This work was mainly
performed within the bounds of the (now finished)
EPSRC funded Project Cross
Viewpoint Consistency in Open Distributed Processing; a more
extensive description of which can be found at
the project
home page.
The particular viewpoints model that inspired this project
was that included in the
Open Distributed Processing
Reference Model (ODP),
which is an architecture for modelling and constructing open distributed
systems. The architecture has been standardised by the
International
Standards Organization
Our work on this topic can be presented under five headings:
Our "framework" papers define the formal concepts underlying
consistency checking. They give a general interpretation of
consistency in terms of the existence of a common development of
the viewpoint specifications and they investigate the feasibility
of checking this notion of consistency. In particular, a number of
different classes of consistency are highlighted and the relative
feasibility of consistency checking within these different classes is
considered.
The following four papers are all centred on our framework
for cross viewpoint consistency. The first is probably the
most complete presentation of the framework. Although
Maarten
Steen's PhD thesis also makes important contributions to the
definition of a formal framework for consistency.

A formal
framework for viewpoint consistency.
H. Bowman, M.W.A. Steen, E.A. Boiten, and J. Derrick.
Computing Laboratory Technical Report 2299, University of Kent at Canterbury,
Canterbury, Kent, CT2 7NZ, December 1999, to appear in Formal
Methods in System Design.

Strategies
for consistency checking based on unification.
H. Bowman, E. A. Boiten, J. Derrick, and M. W. A. Steen.
Science of Computer Programming, 33:261298, April 1999.
 Viewpoint
consistency in ODP, a general interpretation.
H. Bowman, E. Boiten, J. Derrick, and M. Steen.
In E. Najm and J.B. Stefani, editors, First IFIP International Workshop
on Formal Methods for Open ObjectBased Distributed Systems, pages
189204. Chapman & Hall, March 1996.

Cross
viewpoint consistency in Open Distributed Processing.
H. Bowman, J. Derrick, P. Linington, and M. Steen.
Software Engineering Journal, 11(1):4457, January 1996.
Our work on LOTOS
considers how multiple specifications written
in the LOTOS formal specification
notation can be checked for
consistency. The most comprehensive text on this material
is
Maarten Steen's PhD thesis. However, the following publications are also
available.
The following two publications summarise some of the main ideas of
Maarten's thesis.
 Consistency
of partial process specifications.
Maarten Steen, John Derrick, Eerke Boiten, and Howard Bowman.
In Armando Haeberer, editor, AMAST'98, page 15. Springer Verlag,
January 1999.
 Disjunction
of LOTOS specifications.
M.W.A. Steen, H. Bowman, J. Derrick, and E.A. Boiten.
In T. Mizuno, N. Shiratori, T. Higashino, and A. Togashi, editors, Formal
Description Techniques and Protocol Specification, Testing and Verification:
FORTE X / PSTV XVII '97, pages 177192, Osaka, Japan, November 1997.
Chapman & Hall.
The following publication presents some early, but still relevant, ideas on
consistency in LOTOS.
 Composition
of LOTOS specifications.
M. W. A. Steen, H. Bowman, and J. Derrick.
In P. Dembinski and M. Sredniawa, editors, Protocol Specification, Testing
and Verification, XV, pages 7388, Warsaw, Poland, January 1995. Chapman
& Hall.
Some other early ideas of ours on consistency in LOTOS can
be found in the framework papers in the
previous section.
Within the auspices of the Cross Viewpoint Consistency in ODP project
we have also extensively investigated how to check consistency
between pairs of Z specifications. The following paper
highlights the main elements of our work on this topic.
However, a number of other publications can be found on
the Cross Viewpoint Consistency in ODP
home page.
Since different languages and techniques can be used in different
viewpoints, yielding a multiparadigm approach to system
development, it is necessary to relate different formal notations.
In order to investigate the feasibility of relating viewpoint
specifications written in different notations we considered how
LOTOS specifications can be translated into Z, thus, enabling
consistency checking to be performed in Z.
Once again, we have written a number of papers on this topic and
the most comprehensive source for these publications is
the Cross Viewpoint Consistency in ODP
home page. However, the following two papers summarise
the main ideas.
 Viewpoint
consistency in Z and LOTOS: A case study.
E. Boiten, H. Bowman, J. Derrick, and M. Steen.
In J. Fitzgerald, C.B. Jones, and P. Lucas, editors, FME'97: Industrial
Applications and Strengthened Foundations of Formal Methods, volume 1313
of Lecture Notes in Computer Science, pages 644664.
SpringerVerlag, September 1997.
 Translating
LOTOS to ObjectZ.
J. Derrick, E.A. Boiten, H. Bowman, and M. Steen.
In D.J. Duke and A.S. Evans, editors, Northern Formal Methods
Workshop, volume 2nd BCSFACS Northern Formal Methods Workshop of
Workshops in Computing. SpringerVerlag, July 1997.
The original Cross Viewpoint Consistency in ODP project is now
finished. However, a number of directions for further research
have spunoff from this project, e.g.
Some of this work is being pursued within the followup EPSRC
project OpenViews.
Back to Howard Bowman's home page.
Last modified December 1999.