Service Composition in Multi-domain Environment under Time Constraint

Time constrained service composition raises several problems. Researches on QoS-driven service composition provide some preliminary solutions, but there are still some unsolved issues, which can be attributed to the following reasons: (1) the huge time consumption of inter-domain validation, (2) the dynamic execution time of services and (3) the difficulty in defining time constraint due to the opaque feature of composite services. In this paper, we propose a novel service composition algorithm, which models the service composition as multi-domain scheduling problem with minimal service resources and time constraint. Each service is modeled as an exclusive resource during its execution period. By computing the inter-domain communications and available services in each domain, the domain with optimal utilization rate is obtained to arrange services. Meanwhile, loop parallelization is adopted when a service cannot be executed on schedule. Moreover, redundant services of the initial composition are further optimized. Our experiment results show that our approach can effectively achieve service composition with time constraint.