Service Delivery
| DESCRIPTION: | This activity aims at supporting service integrators and service providers by supplying innovative processes, methods, and tools for delivering and maintaining services. The major scientific challenges lie in (i) supporting proper service exposition in a distributed environment, (ii) monitoring the compliance of service behaviour and performance against system requirements, (iii) supporting system reconfiguration in response to service failure or divergence from QoS requirements, (iv) providing usable solutions for identity management. Service exposition is currently supported by means of a distributed service publication infrastructure based on the publish/subscribe primitives. Provides can publish their services and declare their interest for others. The infrastructure is in charge of distributing the information about services to all the interested parties. The publication infrastructure connects SeCSE registries, but can also work with ebXML and UDDI registries. As for monitoring, the activity supports both loose and strict monitoring. The former consists of analyzing the event logs produced by the engine to discover possible deviations. This is done in parallel with the execution, but with some delay. In contrast, the latter adds special purpose probes to the process to check user-defined assertions (in the form of pre- and post-conditions). The execution of the actual business process is suspended every time there is an assertion to check, but the trade-off is between the amount of probing and the capability of detecting incorrect behaviors. The activity also provides an integrated monitoring language, called SECMOL (SeCSE Monitoring Language) to allow service integrators to state their monitoring directives in a seamless way. Fault tolerance is achieved through the use of defensive programming or by means of suitable reaction strategies. Defensive programming is up to the system integrator who conceives the composition, while as for the capability of reacting, the activity integrates with Activity 3 to provide a customizable mechanism to integrate user-defined reaction strategies with the execution of designed compositions. Identity management is required in complex service compositions where the same user (identity) interacts with services supplied by different providers that require user identification. The activity is working on providing viable solutions based on both WS Federation and the guidelines defined by Liberty alliance. |
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