WebComposition Service Linking System: Supporting development, federation and evolution of service-oriented Web applications Martin Gaedke, Martin Nussbaumer, Emma Tonkin IT-Management and Web Engineering Research Group, Institute of Telematics, University of Karlsruhe, Zirkel 2, D-76128 Karlsruhe, Germany, E-Mail: {gaedke | nussbaumer | tonkin}@tm.uni-karlsruhe.de Abstract. There exists a need within many large organizations and their partners to operate cross-organizational Web applications. This paper introduces the WebComposition Service Linking System (WSLS), a component-based and service- oriented system which makes extensive use of Web Services and other standardized Internet technology in order to support development, maintenance and management of reusable and configurable components for cross-organizational Web applications. A real-world application based around the WSLS support system which provides globally accessible core services, NUKATH -- Notebook University Karlsruhe(TH) -- is introduced. Our NUKATH project’s vision is that business processes of universities shall be established, supported, and provided by aggregations of high-quality, ubiquitously accessible, federated services. These federation-aware services could thence be the basis for reusable and standardized business building blocks of a university. Furthermore, these services could transcend the "business" borders of a university – thus allowing for unique meta-structures of distributed universities supporting new collaboration scenarios in education and research. Keywords : Web Service, Reuse, Composition, Federation, Evolution, Component-based Web Engineering 1 Introduction Effective Web Engineering strategies within any large organizational structure such as an enterprise or university ha ve a well- understood dependenc y on effective underlying technologies. A frequently embraced example of such technology is the provision of reusable, configurable components [1, 2]. This constitutes a replacement of previously used ad hoc methods and itself stems from the field of software engineering [3] – it is often considered axiomatic to the field of Web Engineering that reusability is a key concern. Recently, much work within the Web Engineering community has focused on Web Services [4], a standards-based and highly interoperable method of invoking remote procedures, an example of which would be SOAP over HTTP [5]. They provide a powerful approach for the development of new kinds of Web applications that are built by composition of distributed components – typically, any given Web Service exists within a known environment; authentication, data storage and so on are therefore dealt with on a local level, within the parent organization. However, one may easily imagine scenarios in which unique services provided by any given organization ha ve value to Web applications of related Proceedings of the Third Int. Workshop on Web-oriented Software Technology (IWWOST 2003)