A Hybrid Local-Global Optimization Strategy for QoS-Aware Service Composition

This paper presents a hybrid approach for automatic composition of Web services that generates semantic input-output matching compositions minimizing the number of services and optimizing the global QoS. The proposed approach has four main steps: 1) generation of the composition graph for a request, 2) computation of the optimal QoS of the composition graph, 3) multi-step optimizations of the graph to identify equivalent and dominated services, and 4) hybrid local-global search to extract the optimal QoS with the minimum number of services. A validation with the datasets of the Web Service Challenge 2009-2010 is also provided.