Computing and Information Systems - Research Publications

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    Modelling ODP viewpoints
    Sinnott, Richard O. ; Turner, Kenneth J. (ACM Press, 1994)
    This paper gives a brief insight into the current work on the development of an architectural semantics for Open Distributed Processing (ODP). It first provides an introduction to the work on the formalisation in LOTOS and Z of the basic modelling and specification concepts of Part 2, and then focuses on the viewpoint languages of Part 3 of the Basic Reference Model for ODP (RM-ODP). It also shows up the separation of concerns that is achieved through these viewpoints thereby enabling systems to be considered from aspects which might be of interest to different people. This paper also highlights the way in which conformance between these formalised viewpoints can be checked, thereby ensuring that the system as a whole is consistent with the system as a collection of abstract viewpoints of the system. Finally the paper concludes with a brief discussion on the advantages and disadvantages of LOTOS and Z for modelling viewpoint languages and the RM-ODP generally.
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    Applying formal methods to standard development: the open distributed processing experience
    Sinnott, Richard O. ; Turner, Kenneth J. (Elsevier, 1995)
    Since their introduction, formal methods have been applied in various ways to different standards. This paper gives an account of these applications, focusing on one application in particular: the development of a framework for creating standards for Open Distributed Processing (ODP). Following an introduction to ODP, the paper gives an insight into the current work on formalising the architecture of the Reference Model of ODP (RM-ODP), highlighting the advantages to be gained. The different approaches currently being taken are shown, together with their associated advantages and disadvantages. The paper concludes that there is no one all-purpose approach which can be used in preference to all others, but that a combination of approaches is desirable to best fulfil the potential of formal methods in developing an architectural semantics for ODP.
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    Specifying ODP computational objects in Z
    SINNOTT, RICHARD ; Turner, Kenneth J. (Springer, 1996)
    The computational viewpoint contained within the Reference Model of Open Distributed Processing (RM-ODP) shows how collections of objects can be configured within a distributed system to enable interworking. It prescribes certain capabilities that such objects are expected to possess and structuring rules that apply to how these objects can be configured with one another. This paper highlights how the specification language Z can be used to formalise these capabilities and the associated structuring rules, thereby enabling specifications of ODP systems from the computational viewpoint to be achieved.
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    Applying the architectural semantics of ODP to develop a trader specification
    Sinnott, Richard O. ; Turner, Kenneth J. (Elsevier, 1997)
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    Type checking in open distributed system: a complete model and its Z specification
    Sinnott, R. O. ; Turner, K. J. (Chapman & Hall on behalf of the International Federation for Information Processing (IFIP), 1997)
    Type checking is at the heart of distributed systems. The ability to be able to configure objects and have them interwork correctly may well be regarded as the fundamental issue in the development of reliable distributed systems. The type system put forward in the current standardisation activity of Open Distributed Processing (ODP), however, is both and incorrect. The inadequacy is due to the scope of the type system being based entirely on syntactic issues. To achieve reliable interoperability between systems, a type system should deal with behavioural (semantic) issues as well as non-functional issues, aspects of the type that its signature and behaviour do not capture. The incorrectness is due to the syntactic issues not being dealt with correctly. That is, clients and servers have fundamentally different type rules that apply to them. We provide a Z specification of a robust type system that deals with the syntactic aspects of types (correctly) as well as a treatment of the behavioural and non-functional aspects of types.