Anya Sotiropoulou

An active ontology-based blackboard architecture for Web service interoperability

Web services are functional, independent components that can be called over the Web to perform a task. Web services are provided by organizations to enable others to perform tasks the organization offers online. However, with an ever increasing number of Web services, finding the Web service that performs a certain task is not always easy. Furthermore, adopting an end-user point of view what is needed is the actual result and not the service per se. It is often the case that more than one service have to be combined to produce the anticipated outcome, e.g. in the case of life-events. To this end, we propose an active, ontology-based blackboard architecture that aims at tackling the problems inherent in dynamic synthesis of composite Web services and at facilitating user interaction with complex e-government transactions.

Tailoring information systems: an approach based on services and service composition

In recent years, information systems tailorability has been in the centre of research as the need for constructing information systems capable of adapting to change has increased resulting from the explosion of information system complexity. Although a number of approaches and paradigms have been proposed over the years for this purpose, they have not adequately addressed all perspectives associated with tailorability, both from a quantitative, as well as a qualitative viewpoint. In this article, we demonstrate the shortcomings of these approaches and advocate that service-oriented development through the composition of services presents a promising solution to tailorability. For this purpose, we present a particular approach to service-oriented development using soft systems methodology for modelling such systems and service description diagrams for representing root definitions in the design phase of service development. We further proceed in showing why this approach naturally accommodates the requirements behind tailorability.

Pluggable Services for Tailorable E-content Delivery

Deliveringe- content as a service to end users involves addressing various cross-cuttinga spects, including the heterogeneity of source and data, user needs, business rules as well as the evolution of the content itself. Catering for these aspects when modeling information systems calls for an architecture that accommodates evolution through separation of concerns and tailorability, and provides uniform access to the underlying content. Based on the notions of services and servicing rules, modules, providers, and module composition we show that effective modelling of service-based e-content delivery system is accomplished.

A flexible framework for managing temporal clinical trial data

Clinical trials are processes that produce large volumes of complex data, with inherent temporal requirements, since the state of patients evolves during the trials, and the data acquisition phase itself needs to be monitored. Additionally, since the requirements for all clinical trials have a significant common portion, it is desirable to capture these common requirements in a generalised framework, which will be instantiated for each specific trial by supplementing the trial-specific requirements. In this paper, we present an integral approach to clinical trial management, using a temporal object-oriented methodology to capture and model the requirements, a temporal OODBMS for data storage and a generalised template application, through which trial-specific applications may be generated.

A comparison of design patterns and roles in the context of behavioural evolution

Component-based software development focuses on building software systems by integrating existing software components. Central to component-based software development are the notions of reusability, extensibility and adaptability. Components as well as their composition must be easily reused and extended to meet new requirements. Variation-oriented programming is concerned with the incorporation of context-dependent variations in existing object-oriented systems. Based on the principle of separation of concerns, variation-oriented programming addresses - amongst other issues - behavioural evolution and behaviour composition, at runtime. We identify the limitations imposed by the use of design patterns when used for behavioural evolution, in terms of behaviour composition, while at the same time satisfying reusability and extensibility. Then we proceed to present the Atoma framework as an architecture and a means for achieving behaviour composition, as this is guided by the incorporation of context-dependent behavioural variations based on the concept of roles. Roles are considered, in this light, as pluggable behavioural adjustments of an existing object-oriented system.