Current techniques for modeling software architecture do not provide sufficient support for modeling architectural design rules. This is a problem in the context of model-driven development in which it is assumed that major design artifacts are represented as formal or semi-formal models. This article addresses this problem by presenting an approach to modeling architectural design rules in UML at the abstraction level of the meaning of the rules. The high abstraction level and the use of UML makes the rules both amenable to automation and easy to understand for both architects and developers, which is crucial to deployment in an organization. To provide a proof-of-concept, a tool was developed that validates a system model against the architectural rules in a separate UML model. To demonstrate the feasibility of the approach, the architectural design rules of an existing live industrial-strength system were modeled according to the approach.

A basic premise of model driven development (MDD) is to capture all important design information in a set of formal or semi-formal models which are then automatically kept consistent by tools. The concept however is still relatively immature and there is little by way of empirically validated guidelines. In this paper we report on the use of MDD on a significant real-world project over several years. Our research found the MDD approach to be deficient in terms of modelling architectural design rules. Furthermore, the current body of literature does not offer a satisfactory solution as to how architectural design rules should be modelled. As a result developers have to rely on time-consuming and error-prone manual practices to keep a system consistent with its architecture. To realise the full benefits of MDD it is important to find ways of formalizing architectural design rules which then allow automatic enforcement of the architecture on the system model. Without this, architectural enforcement will remain a bottleneck in large MDD projects.

Many product development companies are seeking to remain competitive by reconsidering their development strategies, realising the importance of focusing effort on software innovation. Open Source Software is seen by an increasing number of people as a feasible approach to utilising valuable commodity software development and maintenance, allowing them to concentrating on differentiated software. However, such a change presents new challenges. This paper proposes a three-level approach to preparing a company for leveraging the advantages of Open Source Software. The proposal is motivated through a case study in a company which could be seen as an exemplar of the current state of the art in Open Source adoption in complex domains.

Distributed development (DD) of software systems is an issue of increasing significance for organisations today, all the more so given the current trend towards globalisation. In this paper we present a reference model which can be used as a reference point for any company wishing to review their own DD scenario. This is particularised in two forms, one as an exemplar model for a global (GSD) development scenario and one as a particularisation of this for intra-national DD scenarios. By drawing from eight case-studies on DD, we present ten general strategies for successful DD together with our reference model which characterises an ideal DD situation.

XMI is a standardized format for model interchange between tools. However, XMI-based interchange currently has one great disadvantage: an XMI file exported from one tool is unlikely to import correctly into a different tool. This makes XMI unusable for moving models around in a heterogeneous development environment, leading to increased maintenance problems. We suggest using specialized XSLT transformations to bridge between the XMI dialects of tools, and report on an industrial case study in which the technique has been successfully applied.

Model driven development has several advantages over traditional development, including simplified maintenance. We demonstrate an architecture which, through model driven engineering, allows heterogeneous distributed development of components in a mechatronics application. Key to the approach is an architecture which allows automated and dynamic component integration, together with model sharing through the transformation of XMI files.

This work addresses data warehouse maintenance, i.e. how changes to autonomous, heterogeneous, and distributed sources should be detected and propagated to a warehouse. The research community has mainly addressed issues relating to the internal operation of data warehouse servers. Work related to data warehouse maintenance has received less attention and only a limited set of maintenance alternatives are considered while ignoring the autonomy and heterogeneity of sources.In this paper, we extend work on single source view maintenance to views with multiple heterogeneous sources. We present a tool (PAM) which allows for comparison of a large number of relevant maintenance policies under different configurations. Based on such analysis and previous studies we propose a set of heuristics to guide in policy selection. The quality of these heuristics is evaluated empirically using a test-bed developed for this purpose. This is done for a number of different criteria and for different data sources and computer systems. The performance gained using the policy selected through the heuristics is compared with the performance of all identified policies. Based on these experiments we claim that heuristic-based selections are good.

We address data warehouse maintenance, i.e. how changes to autonomous sources should be detected and propagated to a warehouse. We have extended our work on source characteristics and timings relevant to single source views by exploring data integration from (multiple) heterogeneous sources. We identify relevant maintenance policies and develop a set of heuristics to guide policy choice. On the basis of empirical (testbed) experiments, we claim that resulting selections are good.

Coordination and collaboration are naturally used by groups for carrying out activities and solving problems that require cooperation. However, getting a set of computer agents to do the same has been a problem-primarily addressed by the AI community and recently by the database community as workflow and process management problems. Not surprisingly, the problem has been addressed at different levels of abstraction by the two communities. It is evident that there is a need for bringing the two approaches together to develop cooperative information systems. This paper argues for the use of active databases as an enabling technology for cooperative information systems, details a novel approach for supporting task sharing (a key cooperation strategy within cooperative information systems) using active capability, and elaborates on a methodology for mapping task-shared protocols expressed in high-level speech acts to event-condition-action rules.

Coordination and collaboration are naturally used by groups for carrying out activities and solving problems that require cooperation. However, getting a set of computer agents to do the same has been a problem – primarily addressed by the AI community and recently by the database community as workflow and process management problems (for example, in business processes, electronic commerce, logistics). Not surprisingly, the problem has been addressed at different levels of abstraction by the two communities. Coordination protocols as well as task and result sharing have been investigated by the AI community; specification of alternative transaction models to meet the requirements of non-traditional applications, and their execution have been addressed by the database community. It is evident that there is a need for bringing the two approaches together to develop systems that support cooperative problem solving. This paper – argues for the use of active databases in general and active capability in particular as an enabling technology for cooperative problem solving and cooperative information systems – details a novel approach for supporting task sharing, a key aspect of CPS, using active capability – elaborates on a methodology for mapping task shared protocols expressed in high level speech acts to Event Condition-Action (ECA) rules.

A generalised subtype definition facility is described. A subtype may be restricted in its values, its operations or both. Coercion from a subtype value to a parent type value is always possible. The reverse coercion may or may not be allowed, depending on the subtype. A subtype may or may not use the same form of representation as the parent type. Several examples showing the usefulness of the subtype facility are given. It is shown that, with a few additional facilities, subtypes may be useful in providing data independence in a general purpose language. Finally, it is shown that the concept of subtype is useful in understanding the relationships between certain other programming language constructs.