1 On the Management of Compositions of Web Services

In this position paper, we present our work on Web serv-ices with multiple classes of service, called service offer-ings, and on management and dynamic (i.e., runtime) adap-tation of their compositions. We explain the motivation for Web services with multiple service offerings, present some management and dynamic adaptation algorithms based on the manipulation of provided service offerings, and discuss some of the issues with the corresponding management infrastructure, called DAMSC (Dynamically Adaptable and Manageable Service Components), that we are developing. We also briefly present our work on WSOL (Web Service Offerings Language) – an extension of WSDL (Web Serv-ices Description Language) that enables specification of various types of constraints — including functional, non-functional (QoS – Quality of Service), authorization poli-cies, etc. — and specification of Web services with multiple service offerings. At the end, we summarize some of the challenges for future research in the area of management and dynamic adaptation of compositions of Web services