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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    Business-oriented development of telecommunication services
    SINNOTT, RICHARD ; Kolberg, Mario (Association for Computing Machinery, 1998)
    The development of software for distributed systems, e.g. telecommunication services, is a complex activity. Numerous issues have to be resolved when developing such systems, examples of which are language/system heterogeneity and remoteness of components. Interface definition languages (IDLs) are used as the basis for addressing some of these issues. IDLs allow for the specification of the syntactic aspects of the interfaces of the components in the system to be made. Whilst lending itself to issues of heterogeneity and location transparency, dealing with IDL as the basis for system development is not without its problems. Two of the main problems with IDL are its lack of behaviour and its lack of abstraction. Thus designers should not be constrained to work within the syntactic notations used to implement their systems, nor should they be unaided in how they might better design their systems. In this paper we show how these issues are being addressed in the TOSCA project in its development of a service creation and validation environment.
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    Frameworks: the future of formal software development?
    SINNOTT, RICHARD (Elsevier Science, 1998)
    It could be argued that the primary issue to be dealt with in software engineering today is re-use of software. Current software development rarely, if ever, starts from nothing. Unfortunately, the same cannot be said for the development of specifications. To overcome this problem, various works have attempted to show how specifications can be built using architectural principles. We discuss one such approach in particular, the Architectural Semantics of Open Distributed Processing. We show the limitations of this work with regard to the architecting of specifications and propose a new approach, based on frameworks. To highlight the approach we use the work currently being done in the TOSCA project in its development of a service creation and validation environment for telecommunication services.
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    Engineering telecommunication services with SDL
    SINNOTT, RICHARD ; Kolberg, Mario (Kluwer Academic, 1999)
    If formal techniques are to be more widely accepted then they should evolve as current software engineering approaches evolve. Current techniques in the development of distributed systems use interface definition languages (IDLs) as a basis for the underlying communication and also as an abstraction tool. Object-oriented technologies and the idea of engineering software through frameworks are also widely accepted approaches in developing software. In this paper we show how the formal specification language SDL and associated tool support have been applied in the TOSCA project to engineer telecommunication services using these current techniques.
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    The pros and cons of using SDL for creation of distributed services
    Olsen, Anders ; Demany, Didier ; Cardoso, Elsa ; Lodge, Fiona ; Kolberg, Mario ; Bjorkander, Morgan ; SINNOTT, RICHARD (Springer, 1999)
    In a competitive market for the creation of complex distributed services, time to market, development cost, maintenance and flexibility are key issues. Optimizing the development process is very much a matter of optimizing the technologies used during service creation. This paper reports on the experience gained in the Service Creation projects SCREEN and TOSCA on use of the language SDL for efficient service creation.
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    Experiences of modelling and using object-oriented telecommunication service frameworks in SDL
    Kolberg, Mario ; Sinnott, Richard O. ; Magill, Evan H. (Elsevier, 1999)
    This paper describes experiences in using SDL and its associated tools to create telecommunication services by producing and specialising object-oriented frameworks. The chosen approach recognises the need for the rapid creation of validated telecommunication services. It introduces two stages to service creation; firstly a software expert produces a service framework, and secondly a telecommunications ‘business consultant’ who specialises the framework by means of graphical tolls to rapidly produce services. Here we focus on the underlying technology required. In particular we highlight the advantages of SDL and tools as well as issues and problems incurred.
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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.