Engineering Service-Oriented Systems: Modeling, Discovery and Quality

Service-oriented computing changes the face of modern software by decomposing its application logic. Now business systems can be assembled from loosely-coupled service components developed by various organizations and spread across the world. Service-Oriented Systems (SOSs) incorporate services running on different platforms and hosted by service providers outside of enterprise boundaries. This conceptually new approach to software development poses multiple questions to software engineers. The behaviour of incorporated web services may vary over time, as well as business rules underlying the system. The SOSs should be reactive to any changes in external services, such as service failures or performance decrease. Therefore, discovery of relevant service components and selection of business partners that guarantee good Quality of Service (QoS) are among the prime issues. In this thesis we investigate the problem of developing dependable SOSs from available web services. Firstly, we introduce an approach for conceptual modeling of SOSs, which prescribes a sequence of activities for transforming abstract business processes into service-based workflows. The approach is an extension of the Eriksson-Penker business process modeling framework. Service discovery, risk analysis and QoS-aware selection are parts of the design process. A case study is given to analyze the use of the proposed modeling method. Secondly, we investigate techniques for efficient web service discovery. Our work is primarily concerned with the problem of finding and select-