Model-driven semantic integration of service-oriented applications

In this thesis, we propose a method for the semantic integration of service oriented applications. The distinctive feature of the method is that semantically-enriched service models are employed at different levels of abstraction (from business requirements to software implementation) to deliver flexible integration solutions. In Chapter 2, we start with analyzing the most cited interoperability definitions and derive common characteristics of interoperability. Next, we use these common characteristics to define what interoperability means and identify three different levels of interoperability, namely, syntactic, semantic and pragmatic interoperability. Finally, we study literature from different areas and identify possible interoperability problems at each of the interoperability levels. In Chapter 3, we present a short history of the enterprise application integration (EAI) approaches, discuss their shortcomings and argue what is required to address these shortcomings. We identify three main aspects of the EAI problem. The first aspect concerns the difference in the information models of the systems that have to be integrated. The second aspect concerns the differences in the interaction protocols of the systems. Finally, the third aspect concerns the complexity of building EAI solutions. Service-Oriented Architecture (SOA), Knowledge Representation (KR) and Model-Driven Architectures (MDA) have been proposed as solutions to each of the indentified problems. In Chapter 3, we argue that, since the problem aspects of current EAI approaches always occur together, SOA, KR and MDA should be combined to deal with the problem as a whole. In Chapter 4, we define a conceptual framework for service modeling. The purpose of the framework is to serve as a common semantic meta-model that enables the description, integration and reasoning about (integrated) service-oriented applications. Using the framework one can model the domain of a system, the interactions among its components and their relations, and reason whether these components are interoperable. We expect that our framework will have a wide spectrum of application, e.g., can be used to model services at a business, application and component level, thus beyond the usual domain of web services. In Chapter 5, we present a method for the semantic integration of serviceoriented applications. We start by identifying necessary conditions for semantic and pragmatic interoperability of service-oriented applications. Next, we propose an integration method that enables business domain experts to explicitly specify an integration solution at a higher level of abstraction. The abstract solution is then (semi-)automatically transformed to a software solution by adding technical details by the IT experts. Finally, we present a method to verify formally whether the proposed integration solution meets the identified conditions for interoperability. In Chapters 6 to 9, we validate our integration method by applying it a particular context, using particular technologies. In Chapter 1, we identified a number of requirements for integration methods in general. To verify whether our method meets these requirements we make a number of claims and provide arguments for their validity. We do this by applying our method to in a concrete context using concrete technologies. For that purpose, we solve two integration problems from order management domain and travel domain, respectively. When applying our integration method we observe a number of effects. We analyse our observations and argue to what extent our integration method meets the requirements defined in Chapter 1. Finally, in Chapter 10, we summarise the conclusions of this thesis and identify some topics for further research.