Threshold based query strategies for QoS-aware service composition in dynamic service networks

A challenging task in Service Oriented Computing (SOC) is the selection of the best combination of services that fulfills user's requirements while meeting quality of service (QoS) constraints, i.e. QoS-aware automatic service composition (ASC). This challenge becomes more complex when dealing with various kinds of QoS fluctuation. In this paper, we propose two threshold based query strategies for QoS-aware service composition in dynamic service networks. The strategies, one uses the number of global dynamic services as a threshold, and the more sophisticated one regards the number of dynamic services that affect network structure as a threshold, are applied to decide under which circumstance, either reconstruction or partial adaption to certain Web services construction would show the better performance. We use the Web service dataset provided in the 2009 Web Service Challenge to evaluate the feasibility and effectiveness of the proposed strategies. And the experiments show the well performance of our approach.