S ENSORIA Process Calculi for Service-Oriented Computing ⋆ Martin Wirsing 1 , Rocco De Nicola 2 , Stephen Gilmore 3 , Matthias H ¨ olzl 1 , Roberto Lucchi 4⋆⋆ , Mirco Tribastone 3 , and Gianlugi Zavattaro 4 1 Ludwig-Maximilians-Universit¨ at M ¨ unchen, Germany 2 University of Florence, Italy 3 University of Edinburgh, United Kingdom 4 University of Bologna, Italy Abstract. The IST-FET Integrated Project SENSORIA aims at developing a novel comprehensive approach to the engineering of service-oriented software systems where foundational theories, techniques and methods are fully integrated in a pragmatic software engineering approach. Process calculi and logical meth- ods serve as the main mathematical basis of the SENSORIA approach. In this paper we give first a short overview of SENSORIA and then focus on pro- cess calculi for service-oriented computing. The Service Centered Calculus SCC is a general purpose calculus which enriches traditional process calculi with an explicit notion of session; the Service Oriented Computing Kernel SOCK is in- spired by the Web services protocol stack and consists of three layers for service description, service engines, and the service network; Performance Evaluation Process Algebra (PEPA) is an expressive formal language for modelling dis- tributed systems which we use for quantitative analysis of services. The calculi and the analysis techniques are illustrated by a case study in the area of distributed e-learning systems. 1 Introduction Service-oriented computing is an emerging paradigm where services are understood as autonomous, platform-independent computational entities that can be described, pub- lished, categorised, discovered, and dynamically assembled for developing massively distributed, interoperable, evolvable systems and applications. These characteristics push service-oriented computing towards nowadays widespread success, demonstrated by the fact that many large companies invest efforts and resources in promoting ser- vice delivery on a variety of computing platforms, mostly through the Internet in the form of Web services. Soon there will be a plethora of new services as required for e-government, e-business, and e-science, and other areas within the rapidly evolving Information Society. ⋆ This work has been partially sponsored by the project SENSORIA, IST-2 005-016004 and by the DFG project MAEWA. ⋆⋆ Currently at European Commission, DG Joint Research Centre, Institute for Environment and Sustainability, Spatial Data Infrastructures Unit.