Open Distributed Processing Standards Research Articles

An initial formal model for spatial data infrastructures

The Commission on Spatial Data Standards of the International Cartographic Association is working to define formal models and technical characteristics of Spatial Data Infrastructures (SDI). To date, this work has been restricted to the Enterprise and Information Viewpoints from the ISO Reference Model for Open Distributed Processing standard. The Commission has developed models for these two viewpoints. These models describe how the different parts of an SDI fit together in the viewpoints in question. These models should be seen as a contribution towards the overall model of the SDI and its technical characteristics. During the model development process, the roles of the different Actors in an SDI in the Enterprise and Information Viewpoints have also been identified in Use Case diagrams of an SDI. All the models have been developed using the Unified Modeling Language. ✠ This author passed away in September 2007.

Viewpoints and consistency: translating lotos to Object- z

This paper presents a translation between the formal description technique lotos and the object-oriented specification language Object- z. The need for such a translation lies in the use of formal methods in viewpoint specification, and in particular in the Open Distributed Processing standard. The use of viewpoints as a set of partial interlocking specifications brings an obligation to check the consistency of these partial specifications, and to do so we need to relate specifications written in differing languages. The work presented here aims to support the consistency checking of viewpoints written using formal methods by defining a translation from lotos to Object- z. A lotos specification describes both an ADT component and a behavioural model, the former is translated into the z type system, and the behavioural specification is translated into a collection of Object- z classes where we relate lotos actions to operations in the Object- z specification. A case study is presented, illustrating the translation and consistency checking techniques discussed in the paper.

Constructing an enterprise viewpoint: evaluation of four business modelling techniques

Business process modelling is presented as an important first step in the process of designing a distributed system by integrating pre-existing components. The elements describing a business process are derived from the ODP-enterprise viewpoint language. One of the viewpoints distinguished in the Open Distributed Processing standard is the enterprise viewpoint. This viewpoint describes the organizational context in which the distributed system to be constructed will be used. In this paper we will review four business modelling techniques and their suitability for expressing the enterprise viewpoint is evaluated.

A specification architecture for multimedia systems in Open Distributed Processing

The field of distributed systems is now entering a stage of maturity with work focusing on standards for Open Distributed Processing (ODP). However, it is still important that standardisation remains responsive to new technological demands such as the emergence of distributed multimedia computing. This paper focuses on the likely impact of multimedia computing on formal description within ODP. In particular, a specification architecture is proposed for the formal specification and verification of quality of service and more general real-time concerns in distributed multimedia systems. This specification architecture exhibits a separation of concerns between the specification of behaviour and requirements and also between the specification of abstract behaviour and real-time concerns. The architecture also supports refinement to the computational language defined by the ODP standard. It is important to stress that the architecture does not prescribe the use of specific formal notations or languages; particular specification disciplines can however be developed by populating the architecture with appropriate languages. The usefulness of this architecture is demonstrated by the development of such an approach based on LOTOS together with a real-time temporal logic, QTL. This is applied to a simple multimedia example.

Supporting the real-time requirements of continuous media in open distributed processing

The field of distributed systems is now focusing on standards for Open Distributed Processing (ODP) and entering a stage of some maturity. However, it is important that ongoing standardisation remains responsive to emerging technological demands such as the emergence of distributed multimedia computing. This new field introduces continuous media data types such as digital audio and video which have new, real-time requirements not fully supported in current ODP proposals. This paper describes the results of collaborative research at Lancaster University and CNET, France into the handling of multimedia and continuous media in an ODP environment. The aim of the paper is to present a comprehensive statement of requirements for continuous media in ODP and to aid the evolution of standards by making specific proposals on how the evolving ODP standards could be enhanced.