Open Web Services-based Middleware for Brokering of Composed eHomeCare Services

Generically integrating heterogeneous services eases the deployment of promising eBusiness applications, such as multimedia content delivery, eHealth and eCommerce, all of them covering multiple service and data providers. Integration and composition of services is a complex task since services and applications are built by different vendors, using different programming languages, data definitions and exchange standards. Therefore we describe a middleware architecture that offers dynamic selection and composition of services and automatic load balancing of these services over the available application servers. The architecture also allows the automatic fulfillment of QoS requirements, such as price, availability and response time. The middleware platform translates incoming service requests into an internal composition flow chart. Based on the QoS information from the monitors, the broker selects the best path through the flow chart using advanced broker algorithms. Then the broker starts the chosen services and gathers the result sets, composes them and returns the results to the requester. New application servers and services can transparently be added to the system. Scalability of the architecture at both broker and provider level are also addressed. As example case, QoS brokering for eHealth, in particular eHomeCare, is considered.